Arcana

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Mechanics

Mechanics

Mechanic	Kind	How
Random encounter	By terrain	in a dungeon, about 1 step in 11.6 on one class of tile and 1 in 4 on another, and none elsewhere
Damage formula	Defense as a fraction	attack times (255 − defense) / 256, then row, element, and race factors and a spread of up to about 15%
Growth rate	Fixed gains	each level adds that character's row of six gains, to level 60

Every claim about this game, by concept (28)

general	Rooks needs 20 experience to go from level 1 to 2 and 60,000 to go from 59 to 60. Salah, Darwin and Axs have Rooks' list word for word, Teefa's differs only below level 5, and the four spirits have lists of their own. Each of the nine characters (Rooks, Sylph, Dao, Marid, Efrite, Teefa, Salah, Darwin, Axs) has a list of 60 words, the experience from each level to the next: a level-up raises the level, then sets the experience still needed to the word at the new level in the character's list. No level-up happens at level 60, which is the cap.	Code
	Rooks starts at 150 HP and 30 MP with 10 in each stat, and (computed) his 60 rows sum to 748 HP, 246 MP, 205 Strength, 206 Endurance, 159 Intelligence and 157 Alertness. Each character has 60 rows of six words: maximum HP, maximum MP, Strength, Endurance, Intelligence and Alertness. Row 0 holds the starting values and every later row the gain on reaching that level: a level-up adds the row for the new level, holding HP and MP to 999 and the four stats to 255. A routine that rebuilds a character's figures clears them and adds every row from its level down to 0.	Code
	Each character has a list of 61 counts, one per level from 0 to 60, of the spells it learns on reaching that level, and a list of spell numbers in level order; the level-up routine counts the spells of the earlier levels to find where the new level's spells start. The nine lists hold 81 spells, never more than one at a level: Rooks 13, Sylph 7, Dao 7, Marid 8, Efrite 8, Teefa 12, Salah 13, Darwin 9, Axs 4. Rooks learns the four Call spells at levels 35 to 38, each spirit learns its element's Change Attr. spell first, and Axs learns four spells from level 15 to 30.	Code
	Arcana has 80 monsters. Rimsala's second form has the most HP, 3500; the 16 bosses are numbered 0 to 15, and 30 monsters can cast a spell. Each has a race and element word (the element in the high byte, 1 Wind, 2 Earth, 4 Water, 8 Fire, as the status screen names them, and no bit read as "Man"; the race bits in the low byte, which the race factor reads), Strength, Intelligence, Endurance and Alertness, three equipment numbers (weapon, armor, accessory), HP, experience, level and gold, which is added when the monster falls. The names pair with the stats in table order, as Data Crystal reads them; the boss numbers bear the pairing out, since the 16 numbered monsters are the named bosses, from Stone Guardian (0) to Rimsala's two forms (14 and 15), and the same 16 carry race bit $10.	Code
	Arcana has 81 spells. Damage spells run from 10 power (Lightning 1, Smash 1, Water 1, Flame 1) to 200 (Attribute 11); the Call spells are 180 power at 40 MP; Heal 3 is 999. Attribute 1 to 10 carry two or three elements each and Attribute 11 all four. Each spell, numbered from 1, has a 21-letter name and a field in each of several tables: where it can be cast (1, 2 or 3), one target or all, accuracy, power, an element word whose top four bits are its elements (1 Wind, 2 Earth, 4 Water, 8 Fire), the MP cost and an effect class.	Code
	Every monster's armor defense is 16: the armor lookup reads the first word of its table without the armor number, though the table holds 16 values up to 255 and monsters carry armor numbers 0 to 15. A monster's other equipment numbers pick its battle figures from tables of their own: the weapon number gives a power word, a critical byte and a strength-share byte (205 for every monster), and the accessory number a defense word and a magic-defense byte.	Code
	The spirit in the party has no equipment: the battle code takes its weapon and armor figures from tables indexed by a quarter of its level (which is Rooks' level), 16 steps from levels 0-3 to 60. Weapon power climbs from 5 to 128 and armor defense from 16 to 255, with a critical byte of 10 and a strength share of 102 throughout; magic defense goes from 0 to 120. Its accessory defense is read without the index, so it stays 16 at every level.	Code
	96 of the 120 pieces of equipment can be equipped by someone; the rest are placeholders such as "Sword 1" and "Armor 15". Each piece, numbered from 1, has a 16-letter name, a price word, a byte of who can equip it (one bit each for Rooks, Teefa, Salah, Darwin and Axs; the spirits none), a power word that is attack for a weapon and defense for the armor and third slots, a race and element word, a byte that is the critical chance for a weapon and magic defense for the third slot, a strength-share byte, and a spell byte, which the battle code reads for the weapon. The Undead Blade's race bit (1) is the one the undead carry, the Dragon Blade's (2) the four dragons', and Desiree carries both 2 and 8.	Code
	Arcana has 17 items and 7 cards. The items run from the Return Ring to the Enchanted Jewel, six of them Honeys; the cards are the four element cards, the Null Card, the Fog Card and the Call Amulet. Each kind is numbered from 1 and named in a table of its own, each name ending at a 0 byte: item names 20 bytes apart, card names up to 11 letters, 11 bytes apart, the last one running to 12 bytes.	Code
	The game has 135 chests (10, 34, 43, 25, 23 by chapter): 78 items, 15 pieces of equipment, 18 cards and, computed, 24 gold chests worth 10,200 GP in all. Each chapter has a list of chests, 12 bytes an entry: the map, the x and y of the chest's tile, a word the chest drawing uses, the contents type (card, item, equipment or gold) and its number or amount. A chest is found by its map and tile, and an opened chest is empty.	Code
	A monster whose spell byte isn't 0 chooses its spell 1 time in 2 while its HP is above half its maximum, and 3 times in 4 at half or below.	Code
	Reaching level 60 gives Rooks +100 HP, +30 MP and +10 in each stat, against +6, +2, +4, +2, +2, +2 at level 59: the level-up adds the row for the new level, and each character's table has rows only for levels 0 to 59, so level 60 adds the next character's starting row (Sylph's, for Rooks); for Axs it is the 12 bytes after the table. Level 60 is the cap, and its experience still needed is cleared.	Code
	The spirit in the party has no experience of its own: its level is set to Rooks' whenever his goes up, the experience routine returns at once for its slot, and its equipment figures come from tables by a quarter of that level (arcana-tables/spirit-equipment). A spirit, Teefa or Axs joining the party takes Rooks' level.	Code
Boss fight	Only chapters 1 to 3 have boss tiles, 5 in all (Stone Guardian, Iron Guardian, Cyclops, Efrite, Hydra); chapters 4 and 5 have empty lists, so their bosses start some other way. Each chapter's list gives a boss tile's map, x, y and the group to fight; stepping on a listed tile whose entry's flag is clear starts that group's battle for certain.	Code
Boss fight	Before a spell rolls, a check turns some away: a target with race bit $10, which all 16 boss monsters carry, ignores every checked spell whose element word lacks bit $10: Chaos Wind, Entomb and Destroy, the ten paralysis, petrify, stop, sleep and confusion spells, Requiem, Emancipation, Final Liberation, Ruinous Mission and Flee, and a spell with bit 1 (Requiem, Emancipation) affects only targets with race bit 1, the undead.	Code
Damage formula	A weapon hit's damage, with each product rounded down to a whole number: attack = power x (Strength figure x share / 256 + buff + 205 - share) / 256, where the Strength figure is Strength x 191 / 256 + 64, share is the weapon's strength-share byte, power is the weapon's power word (10 bare-handed), and buff is 25, or 50 with one of the attack flag bits set and 0 with the other. Defense = armor x 102 / 256 + shield x 51 / 256 + (Endurance x 223 / 256 + 32) x 51 / 256, plus 25, 50 or 0 by its own two flag bits. The damage is attack x (255 - defense) / 256, times the row factor (1, 1, or about 0.88, 0.76 or 0.64), the element factor, the race factor, 0.75 when bit 8 of the target's state is set and 2 on a critical, before the random spread.	Code
Damage formula	Healing spells skip the roll to land, and spells of effect class 8 and up (from Dodge All on, arcana-tables/spells) always land; Ruinous Mission and Flee face only the immunity check. Every other spell rolls to land: chance = its accuracy + the caster's magic figure - the target's, where the magic figure is (Intelligence - 55) x 66 / 256 and 0 below 55 Intelligence; Chaos Wind, Entomb and Destroy add 52 to the caster's side when the element factor is 1.6 and to the target's when it is 0.4. It lands when a random number modulo 255 is below the chance (capped at 255; below 0 it misses). A damage spell then deals power x (205 + (Intelligence - 55) x 393 / 256) / 256, times (255 - magic defense) / 256, then add 1, times the element factor, before the random spread; magic defense is the shield's byte plus (Intelligence - 55) x 99 / 256, capped at 255. Healing spells give their power plus a spread of 13/256.	Code
Damage modifier	Damage gets a random spread on top: with S = base x 38 / 256 + 1 (at most 255), the result is the base plus a random number modulo S, then held between 1 and 999. A base of 100 comes out 100 to 114. Healing spells use 13 in place of 38.	Code
Elemental weakness	The four elements form a cycle: Wind is strong against Earth, Earth against Water, Water against Fire and Fire against Wind (1.6 times), each element is 0.8 times against itself, 1.2 against the element two steps on and 0.4 against the one that beats it. An attack with several elements takes the average of their factors plus 13/256 for each element past the first, so one with all four does about 1.15 times against any element. A target without an element takes 1 times, plus the same 13/256 for each attack element past the first. A target with several elements is judged by the first of Wind, Earth, Water; the attacker's element is its weapon's, else its own.	Code
Fleeing	A boss in the battle stops running: if any fighter has race bit $10, which all 16 boss monsters carry, the run command prints "But there was no escape." What happens when no boss is present, and whether that path can still fail, was not read.	Code
Hit chance	A weapon attack hits when a random number modulo 255 is below the hit chance: the attacker's accuracy less the target's evasion plus 245, capped at 255 (a result below 0 also reads as 255). Accuracy is 3 x (Alertness / 8 + 1) plus 64; one of its two flag bits sets the 64 to 127 and the other to 0. Evasion is the same figure from the target's evasion flags, plus 26 when bit 8 of the target's state is set and a row term of 0, 0, 26, 51 or 76. The same random number makes the hit a critical when it is also below the weapon's critical byte.	Code
Random encounter	The five chapters hold 52 monster groups for random battles. 35 of them list five monsters and use a set of 16 formations, each placing one to eight monsters by their place in the group; the boss groups list one or two. A dungeon tile's encounter value picks the group in its chapter's list of up to 16. A group is a byte whose low four bits count its monsters and whose high four bits pick the battle music, a byte naming one of 12 formation sets, then the monster numbers.	Code
	The 12 formation sets hold 102 formations. Sets 1, 4, 5, 7 and 9 each hold one formation of one monster, used by the bosses and the Mimic; set 8 is Darah and Barah together. A random battle picks one of its set's formations by a draw out of the set's count, so each formation of a 16-formation set comes up for 16 of the 256 values the draw maps from. A set is a count, then that many formations, each a count and pairs of bytes: a position and a place in the group (A for the group's first monster to E for its fifth).	Code
	In a dungeon a step can start a random battle, about 1 step in 11.6 on one class of tile (computed: a draw out of 12 coming up 0, 22 of the 256 values the random byte can take) and 1 step in 4 on a second class (computed: a draw out of 4, 64 of 256); every other tile starts none, except a boss tile. The tile also picks which of the chapter's monster groups appears. A boss tile with an entry in the chapter's boss list starts that entry's battle for certain while the entry's flag is clear; once the flag is set the tile starts nothing. A chest tile opens its chest instead.	Code
	A random battle draws its opening out of 32: 0 gives a first strike and 1 an ambush under the banner "Yikes!!" (8 of the 256 random values each, computed), 2 to 31 an ordinary start under "COMBAT". In an ambush the party sits out the first round: party members are skipped until the first monster acts. A first strike is meant to skip the monsters, but it is cancelled on the first party member taken, before any monster comes up, so those battles play as ordinary ones and show "COMBAT". A scripted battle opens ordinarily, or as an ambush in one scripted case.	Code
	The spell list has two field spells meant, by their names, to reduce encounters: diminish Encounters (4 MP) and diminish Encounters 2 (8 MP). What they change is unread; the step routine's roll reads only the tile's value.	Unsourced
Turn order	Each round the game draws who acts next, with chances in proportion to a quarter of each fighter's Alertness (at least 1): it sums those weights over the fighters taking part, takes a random number modulo the sum, and picks the first fighter whose running total is above it.	Code
Type effectiveness	Monsters carry race bits (bit 1 marks the undead), and a weapon hit scales by them: when neither side has race bits of its own the factor is 1; otherwise it is 1.2 when the attacker's race bits, its weapon's included, meet the target's, and 0.61 when they don't. A party member has none of its own, so it hits a monster with race bits at 0.61 unless its weapon carries a matching bit, and at 1.2 with one. Against a party member, the target's bits are the ones its armor and shield don't carry, so a monster with race bits hits at 1.2 unless the defender's armor or shield carries all of them.	Code