Randomizer / disc patcher

Tier B. The drop is the byte pair at +0x48 (item) / +0x49 (chance) of the decoded monster record; each edit is decompress → mutate → recompress → zero-pad of that monster's slot. A slot too tight to re-pack is skipped and reported. See battle data pack and the tier B write-up.

Tier E code hook. A record has one drop slot, so no data edit can make a monster drop two things; instead the battle-end reward routine is detoured after it grants the normal drop. The injected routine rolls rand() % 100 < chance with the battle RNG, picks an id from an embedded equipment table, adds it, replays the two displaced instructions and returns. It runs once per battle.

Equipment ids are recovered by name: the curated gamedata weapon / armor / accessory names are matched case-insensitively against the disc's own item-name table, so no Sony bytes ship. The rate is tiered by gear price (early ≤ 3700 G, mid ≤ 17000 G, late above) and by monster EXP (early ≤ 600, mid ≤ 3000, late above), taking the lower tier: 3% / 2% / 1%. Sub-percent rates are unrepresentable because the retail roll is integer.

Tier C. A chest grants its item through the field VM's GIVE_ITEM opcode 0x39, a single inline operand byte in the scene's script. The sites are found by an opcode-aware walk that skips inline dialogue segments (a byte scan would false-hit a 0x39 inside text) and is bounded to each record. The chest's announcement names the item again through a separate dialogue token 0xC2 <id>; both bytes are rewritten together (display vs grant) so the flavour text matches the grant. Scenes arrive as either a bundle MAN or a raw streaming chunk; both carriers are walked, so the streamed dungeons (Mt. Rikuroa, Mt. Balden) join the pool. A scene too tight to re-pack keeps its items and its ids leave the shuffle pool.

Keep-static items. The protected set is derived from the disc, not a hand list: every named item the item table prices at 0 (the game's own “never sold” marker) minus the chest-found gear that is merely unsold (the Ra-Seru set and the Astral Sword). A protected chest keeps its item and its id never enters another chest.

Tier C. A gold merchant's stock is inline in the scene MAN, in the payload of field-VM op 0x49 sub-op 0: [u8 count][count × u8 item_id][ASCII name\0]. Sites are found by a signature scan rather than an opcode walk, because a confirm-picker ahead of the op desyncs a linear walk; strict validation (sub-op byte, small count, non-zero ids, printable name, id names a real item) rules out false hits. Item ids are rewritten same-size and the MAN recompressed. The chest-only Ra-Seru gear and Astral Sword ship at price 0, so the pass first prices them (approximated from the nearest priced gear of the same type) with a same-size SCUS edit.

Tier A. The prize list is a static table in the menu overlay's data segment (PROT entry 899, stored raw): four 0x60-byte blocks of 8-byte [u16 item][u16 story-gate][u32 coin-price] records. It debits the casino coin bank, not gold, which is how it is told apart from a merchant. Same-size raw edit, no LZS.

Tier A. The steal table is a static SCUS_942.54 table of [chance, item] per 1-based monster id - not part of the monster record. The item byte is overwritten straight into the executable; nothing can overflow, so nothing is ever skipped.

Tier A. Each prize is a raw 12-byte row [u32 limit][u32 price][u32 item] in the fishing-exchange table (parser legaia_asset::fishing_exchange); rows can be repriced, not added, removed or swapped. See the fishing minigame and the spirit fish write-up.

Tier C. The threshold is a script literal in the Sol Tower scene MAN, rewritten same-size and recompressed.

Tier C. Formations are encounter records [3 reserved][u8 count][u8 ids] inside the scene MAN; monster id bytes are rewritten and the stream recompressed. Both MAN carriers are walked (bundle MAN and raw streaming chunk), so the v12-family dungeons are covered.

Boss protection. A formation is random only if some region with a non-zero encounter rate reaches it; formations the script starts by index (bosses, story fights) stay byte-identical and never enter a donor pool. An explicit id guard pins Gimard, whose tutorial formation a rate>0 region happens to span.

Solo-strong pass. Each monster is scored by its combat-stat budget; each scene's baseline is the mean of its original random monsters. Any multi-monster random formation whose strongest member clears the threshold is cut to that monster alone (same-size: count set to 1, rest zeroed). Wider scopes work because the battle loader streams any monster's slot by id on demand.

Tier B. Stats are u16 halfwords at fixed offsets of the decoded monster record (HP +0x0C, MP +0x10, then ATK / DEF↑ / DEF↓ / INT / SPD). The pass is column-wise: shuffle permutes one stat across the roster (multiset preserved), random draws each cell from that column. The AGL action gauge (+0x0E) is excluded because it gates the AI's action economy. Protected ids (the Rim Elm sparring partner, the first wild Piura, every story-boss form) are neither source nor target. Each slot re-packs to 0x14000.

Tier B, same seven halfwords as the stat shuffle. Integer permille arithmetic ((v * permille + 500) / 1000), zero stays zero, non-zero floors at 1, saturates at u16. Bosses are scaled - a difficulty knob that skipped the set-pieces would miss the hardest fights - except the unwinnable Rim Elm sparring partner, pinned in both directions. AGL is left alone so a 5x run is harder, not a slideshow of enemy turns; EXP, gold and drops never move.

Which enemies are bosses is read off the disc through the encounter randomizer's mask (a monster seen only in script-started formations), unioned with the curated story-boss list for the mid-battle forms no formation names, and with the tutorial enemies forced back to regular. The loader's own fixed ATK / DEF / INT boost applies on top when a record becomes a live actor.

Tier B. One field is the whole feature: the base EXP halfword at decoded-record +0x46, which the victory-spoils routine (×3/4, split among living members) and the run-away EXP hook both read. Same permille arithmetic and clamps as the difficulty scale.

Tier B. A killing physical blow rolls a d100 against the record's catch byte (+0x3F) when its Seru id (+0x3E) is non-zero; retail rates run from 80% (Gimard) to 1%. The byte is overwritten and the slot re-packed. Seedless.

Tier B. The hit count is not stored: the AI queues strikes while a per-round AGL budget (the record's AGL stat) affords each attack move's AGL-cost byte, bounded at 15. The dial divides each retail-affordable cost byte by the multiplier (round half up) and clamps it to the budget, so an attacker always keeps at least one hit. Sentinel, overpriced and zero-cost entries and spell casts are byte-identical; AGL itself never moves, so this composes with the difficulty scale.

Tier A. Only the +0x00 power halfword of each 26-byte move-power record moves (the roll modulus the damage kernel reads); the other 24 bytes - geometry, timing, effect and sound cues - are untouched. PROT entry 898 is stored raw, so the write is same-size in place.

Tier A. Cells are damage-scale percentages (100 neutral, >100 weak, <100 resist, 0 immune) in matrix[attacker][defender] inside PROT entry 898 (raw). Shuffle permutes the 64 cells; random draws from them. See battle formulas.

Tier A. The cost byte at record +3 of the static spell table in SCUS_942.54; names and target shapes untouched.

Tiers A + B. A combo lives in two files that must change together: the matcher records in each character's player battle file (LZS, rewritten in place) and the SCUS arts-name table's menu-arrow glyph string. Display strings are deduplicated across characters, so the assignment permutes distinct combo strings per length class. See art records.

Tier B. An art's 1–4 per-strike power bytes sit at +0x24 of its 0xD0-stride record in the character's player battle file; a byte is a tier, mult = [12,18,20,22,28][(v-0xC)%5]. Every active byte of the matched record is set (hit count preserved; a spirit-only art with no damage byte is skipped) and the record recompressed. There is no menu copy to sync. A combo shared by two characters edits both files.

Tier B. A Super Art has its own 0xD0-stride record (name at +0x10, power bytes at +0x24) indexed by action constant: base + (c - 0x10) * 0xD0. The finisher constants are known, so the address is derived and self-checked against the record's name; an unrecognised build yields nothing. To make a Super cheaper to set up, retune its chain arts with the AP override - the browser's Super Art row names them and offers an Add rows button. No per-Super AP field is injected.

Tiers E + F. Performed is a per-character bitfield in the one free, save-persistent byte of the character record (+0x75D, the sixteenth learned-id slot no fifteen-art character reaches), set by a two-word detour at the Super applier's match arm. It rides in the save block, so rows survive a save/load.

A row's AP is the chain's sum, read off the arts-name table at patch time; its name is chased from the live art record; its arrows are the Super's physical input derived by the byte-exact retail tokenizer (arts overlap, so Tri-Somersault is seven arrows). The battle list synthesises a 20-byte arts-table record in dead space and jumps the list renderer past its scan into its own hit arm, so retail draws every field; the pager is replaced in place so pages step. The pause-menu half detours the menu overlay's panel renderer with routines hosted in that overlay's dead runs. Both halves are verified live under PCSX-Redux. Known cosmetic gap: the Triangle prompt's page caption can still read “View Hyper Arts list” on a later page.

The battle-list half needs 613 bytes of the 652-byte verified-dead SCUS arena - hence the exclusivity; the arena budget explains why it cannot move into the battle overlay.

ZetaPhoenix authored the payload as a GameShark-style RAM patch: a 3764-byte block at 0x801FD000 holding trigger tables, fifteen names, four MIPS routines and seventeen animation edit-lists. It is installed unmodified: parked in the DMY.DAT annex and streamed in by a twelve-instruction stub entered from battle init, one instruction after the battle overlay's own CD read finishes. That address is free RAM in every state of the project's save library, with no overlay covering it.

Fourteen same-size word edits across ten sites point the game at it - ZetaPhoenix's own hook set, supplied by him and installed verbatim: seven retarget the retail Super-Art applier onto the pack's wider tables (doubling one register turns the 5-row strides into the pack's 10-row strides, and the match arm's exit seed widens with the loop bound so a match still ends the scan), the rest jump into his routines. The one addition is the battle-load stub and its hook, this project's by construction - his RAM patch had nothing to load. New arts: Vahn - Ultra Elbow, Somersault Duo, Searing Rush, Criss-Cross, Blazing Typhoon; Noa - Double Lizard, Falcon Talons, Chilling Smash, Zephyr Swipes, Grand Maelstrom; Gala - Ground Pound, Storm Kick, System Shock, Skyvolt Knee, Raging Bull. The pack also ships the author's fix for retail's mis-centred art name banner (the banner is measured against a placeholder name and only re-measured for regular/Hyper arts), its routine parked behind the battle-load stub - his instruction stream verbatim, relocated out of the SsAPI zero-padding window to read-watch-verified arena space. His licence is to be confirmed before a tagged release ships it.

Tier E. Retail has no per-art AP number - it computes the cost from the art's position in the character's list - so one code hook into the party arts queue-builder (PROT 0898; party slots only) reads a 4 × 32 i8 config table keyed by (character, arts row) hosted in the verified-dead SCUS arena, which is why it is exclusive with the other arena features. Each targeted art's menu AP byte (+2 of the arts-name record) is rewritten to match. Sites and AP math: arts command gauge. Disc-verified; a live battle playtest is what would make it runtime-verified.

Same-size immediates inside the battle overlay (PROT 0898), no arena. Spirit is the per-action accrual the battle-action state machine adds in its state-0x50 cleanup (8 per action, 0x20 for Spirit) plus the three gauge-widget ramp targets that mirror it, so the animation stays honest. Damage is pct = max(1, damage * 100 / max_hp); the 100 is a shift/add chain, restated as an explicit multiply for any other factor, and it is inlined twice (the closed-form finisher for magic / specials, the arms resolver for physical hits) - the patch writes both and refuses an image whose copies disagree.

The signed accrual tail

The gauge is a u16 and every retail site clamps only against the 100 ceiling, so a negative value needs a floor the consumer honours. On the damage site the dead ceiling words host a bgez floor. The Spirit tail is shared with the +8 every action grants, so the floor and the surviving ceiling do not both fit; they fit because a negative setting makes the AP-Boost-1 arm dead, and its head hosts the relocated over-100 clamp. Consequence: while a slider is negative, the AP-Boost accessory arm is inert. Negative modes are statically verified only. The assembled tail is listed on the internals page.

Tier A. The [INT, ATK, UDF, LDF, SPD] tuples of the static equipment table in SCUS_942.54, permuted within slot category. Rows are edited, not item ids (several items can share a row), and unreferenced rows are left alone. Composes with the mask pass, which edits the disjoint +6 byte.

Tier A. The +6 equip-character mask (1 Vahn, 2 Noa, 4 Gala, 7 any) of the same table, permuted within slot category (+7 & 0x60). The engine's equip picker reads the same byte, so a patched disc re-gates it there too.

Tier B. The arm cost is not a runtime class check but a per-(character, weapon) byte baked into the player battle files; each weapon section is decompressed, the byte rewritten for the new relationship, and recompressed in place. See arts command gauge.

Command cost (tier B): each of the four commands is priced by the equipment section that fills it in the character's player battle file - Left and Right by the weapon and the Ra-Seru arm, Down and Up by the footwear's two records (:up). The cost byte is the AP a press charges and the pennant width plus 6. An item the file has no section for falls to the section's default record. Applied after --weapon-specialty, so a named cost wins.

Equip owner (tier A + B): rewrites the item's mask in the SCUS table, then for a weapon cuts the model out of the donor file's record, re-seats it into the new owner's grip (calibrated per weapon class from the weapons both files carry) with the donor's texture tile, palettes and arm cost. Room comes first from re-packing the three player files (PROT 863..865) with the optimal LZS parse, then from parking the rebuilt records in the DMY.DAT annex the loader reaches by descriptor offsets alone - same-size image, still a PPF. Ra-Seru forms, body, head and footwear are never carried over. Details: battle data pack.

Tiers A + D. There is no starting-inventory table: the new-game init routine builds the bag in code, so the seed code is rewritten in a reclaimable 40-byte region, one packed halfword store per slot (cap 7, or 5 with all-warps). Overflow is granted by splicing a guarded run of silent GIVE_ITEM ops into the opening scene's entry script through the MAN relocation engine.

The starting level is three coordinated SCUS edits: the level literal on every roster slot (magic rank kept at 1); each growth character's cumulative XP seeded to the midpoint of level N's band and the next threshold to reach(N+1) from the disc's own thresholds; and each stat template recomputed from the disc's growth curves (Terra has none). See new-game table, save record, level-up.

Places with a label but no quick-travel cell (Hunter's Spring, Sol Tower, …) are addressed by name; matching is exact, so Conkram leaves Conkram (Past) alone. The rename runs in the door randomizer's slot, after a language pack. See place names.

Tier E. The battle-action state machine's successful-escape teardown state runs once per escape, after party HP has been floored to 1; its first two instructions are detoured to a routine in the SCUS rodata gap that sums each live enemy's EXP halfword, scales it, adds it to every member's cumulative-experience cell (capped at 9,999,999) and returns. The grant is banked, never a level-up mid-fade. The routine shares the gap with the equipment-drop hook, clear of it, so both battle hooks coexist.

Tier E. A battle-setup hook sets the game's own AI-delegated confuse/charm flag (+0x16E |= 0x380) on the frontmost enemy, and a one-word widen of the victory check stops the ally counting as an enemy left. A bundled charm_fix guard closes the hard-freeze the widen otherwise arms: a living ally can be the acting actor at victory, and the win-pose staging would index the 3-byte party roster with a monster slot; a single-word detour keeps the acting slot only when it is a living party slot. See the battle action SM.

Tier E: nine same-size detours into SCUS regions verified dead and outside every live indexed table (618 of the arena's 652 bytes). “Capturable” is an allowlist built at patch time from the disc's monster names matching the player Seru-magic names; the permanent flag is a parallel per-spell byte inside the saved character record, so it survives a memory-card save. See spell table.

Tier F. Hand-assembled MIPS hosted entirely in the menu overlay's (PROT 0899) reference-free dead region: a fourth Buy / Sell / Trade / Quit row, a Wants / Offers screen, and a “No <want> available” message when nobody holds the wanted Seru. Levels are curved low (1-3 common, 7-9 very rare); offers rotate on a play-time bucket, phased per vendor by an offset summed from its shop record, all deterministic from the seed (kernel legaia_asset::seru_trade).

Same-size retargets of those casts' damage path onto the ordinary elemental route. See battle formulas and cast modules.

A monster approaching an out-of-reach target waits in a range poll with no movement code and no timeout while its staged Move clip carries it; when a summon's staging round-trip precedes the melee, that clip dies and nothing re-stages it. The fix is a nine-word rewrite of the poll's redundant per-frame facing recompute: when the clip reads dead while the poll still fails, the state bounces back to staging and retail's own code resumes the walk. Runtime-verified on both live-caught park states. Full story: the endless camera orbit.

A koin1 script edit grows the enrollment picker to its four-option ceiling, plus a small arena/SCUS code injection. The 1v2 fits the battle heap by streaming slim clones of Che and Lu from two unreferenced archive slots; the real records, the ravine duels and the Master course are untouched. The pair fire their specials once every four turns, staggered two apart. Gi borrows two streamed capture-class casts - Divide below half HP (after which Blazing Slash is locked out and the clone only melees) and Spore Gas from turn 3. Losing returns you to the Sol venue; the course repeats.

With custom items on, a clear also hands out Nature's Elixir, the Ra-Seru Tear and the Fury Bloom in place of the Honey reward.

Tier A + E: name, description and effect-descriptor rows written into the three free slots of the item table and item effect table, with the effects hosted as code hooks.

Each character keeps their animations, arts, magic, stats and story but wears the mapped sibling's battle model; each sibling's monster block is rebuilt around the mapped hero's model, and because the animation streams pose parts by index, a same-part-count model inherits every move. The swap is an anatomy permutation plus a per-part rest-pose bake between the rigs and a bit-exact 4bpp texel re-layout between the monster page and the party texture band, applied to every equipment variant of the player files. Field models rebuild from the siblings' Nivora Ravine NPC meshes; battle grunts resample from their voice banks; save-select faces, memory-card icons and load-screen portraits follow the mapping; every dialog line naming a sibling is rewritten. Pause-menu portraits and battle HUD faces stay retail.

The signature special lands when it connects

The reskinned Hyper Art plays the sibling's multi-stage signature chain, and its damage frames and visual burst are re-derived onto the frames the chain actually connects on: a stage with authored contact beats (Lu's strikes) uses them; one without (Gi's and Che's, damaged by cast modules as enemies) takes the frame the whole body arrests hardest. Anchoring on the final stage's start instead lands the first hit 1–3 seconds late, because that stage opens with its own approach.

Each slot fights in its sibling's element

Retail keeps one element byte per character in the battle overlay (Vahn fire, Noa wind, Gala thunder), read by both affinity readers. The swap copies each sibling's element from their monster record - Gi fire, Che earth, Lu thunder - into the slot, so Lu's Plasma Strike deals thunder out of Vahn's slot. It is per character, not per art.

Move set

Hybrid changes nothing but the one reskinned Hyper Art. Delilas rebuilds the character's whole battle-animation archive from the sibling's monster clips (the signature, the locomotion clip and one entry per distinct swing), repoints and re-times every art, renames each surviving art after the clip it plays, and blanks the combos of arts neither a Super Art nor the Miracle Art needs - a blanked combo is never performed, so never learned. The archive is rebuilt rather than extended because retail leaves too little free space (Noa's slot has room for no extra clip); repeated names are also what keeps the art bank inside its compressed footprint. Result: 12 / 16 / 12 performable arts, 3 / 1 / 3 hidden; Super and Miracle Arts remain reachable.

Arts voices

Original leaves the retail XA arts shouts untouched. Adjusted re-voices them toward the mapped sibling through a tuned pitch/formant map. Removed silences the XA2/4/6 arts banks and the party's three swing-grunt channels, routing intact, leaving the resampled battle grunts. The grunt resample is SPU-side and rides with the swap in every mode.

Tier D - the only randomizer that resizes an asset. The field VM's 0x3F named-scene-change op carries [i16 index][u8 name_len][name][entry_x][entry_z][dir] inline in partition-2 MAN records; the destination name is variable length, so the op is rewritten through the relocation engine, the MAN recompressed and the descriptor's size word updated. The whole destination (scene + entry tile + facing) moves as one unit, so a re-pointed door always lands somewhere valid. Doors with no reverse partner fall back to one-way and are reported; a scene whose MAN cannot grow in its footprint keeps its doors.

Tier C. Entering a house is an intra-scene reposition: the cross-context player move 0xA3 0xF8 xb zb (opcode 0x23 | 0x80 into the player channel), in partition-0 records paired by a fullwidth naming convention (ＩＮ/ＯＵＴ, 入口/出口, Ａ/Ｂ elevator endpoints). 56 warps across 12 scenes; a same-size 2-byte operand edit, recompressed in place. A record carrying several player warps is choreography (the tower's multi-stop elevator), not a door, and stays vanilla.

Same-size 2-byte writes into the raw .MAP sectors - the per-scene field map's trigger block carries a kind-0 sub-table of [tile_x][tile_z][dest_x][dest_z] records with no object, record or name; landing is (dest_x*64 + 64, (dest_z+1)*64). Records have no entry/exit class, so the softlock policy is reachability verification: the walkable surface (walk-visible floor minus collision wall bits) partitions into 4-connected components, each record is a directed edge, and a permutation is accepted only if the component graph keeps every retail reachability pair and adds no one-way trap - retried deterministically, vanilla when nothing verifies. Endpoints that cannot be attributed on the base grid stay vanilla. See field locomotion.

The battle loader streams a monster's slot by id on demand with no per-scene preload list, so a formation byte alone makes a cut monster spawn. The unnamed accessory's name string is written into preserved rodata padding of SCUS_942.54 and only 0xFD's name pointer is repointed; the region is chosen by its flanking rodata surviving file→RAM byte-for-byte, since the data segment's trailing zero-fill is scratch the game overwrites every frame. The accessory's documented effect (only Seru-class random encounters) is never exercised in retail, so treat it as experimental.

The encoder copies the original's pixel mode, CLUT layout and VRAM placement fields (TIM); alpha maps to the semi-transparency bit. A raw-tier texture always applies; an lzs-tier one only when its section re-compresses into the original footprint - the battle-equipment art is the tightest, with as little as two spare bytes in one record. A monster sheet is shown through the palettes its model uses and its palettes are never rewritten. Browser change packs carry your images plus a fingerprint of each retail texture, never the game's pixels. See also NPC palettes and save icons.

The part-count law: battle animations pose TMD objects rigidly by index with no skeleton (monster animation), so a replacement with the retail object count inherits every move; the importer rejects any other count. Material names carry render state (skin_pNN, skin_semi_abrN_pNN, flat) so a round trip reproduces the palette partition; faces without a hint are re-palettized greedily into at most 15 sixteen-colour CLUTs. The block is re-packed into its 0x14000 slot and the patched image re-decoded before success is reported. Two worked examples ship in the repo. See TMD and the bestiary.