Breath of Fire II:ROM map
The following ROM data was obtained from an old Gamefaqs thread (link) by a user called StarryKnights.
Characters starting information
Initial data for the game's characters. Information block starts at x00:087C ($C0:087C) and ends at x00:0D3B ($C0:0D3B) (Assuming no header). Each entry is 64 bytes long. Layout: 1-4: Character Name 5-6: Unknown, 00 for all. 7: Character's PC Number 00 - Ryu 01 - Bosch 02 - Rand 03 - Katt 04 - Nina 05 - Jean 06 - Sten 07 - Aspara 08 - Deis 09 - Kid Ryu 0A - Kid Bosch (Zombie in battle) 8: Initial level 9-10: Unknown 11-12: Initial HP 13-14: Unknown; always the same as initial AP. (Possibly Unused) 15-16: Initial AP 17: Character portrait/sprite modifier; 00 for everyone 18: Initial Strength 19: Initial Stamina 20-21: Initial Agility 22: Initial Condition 23-24: Initial Weapon (Value 11 tells the game that you have a weapon equipped) 25-26: Initial Shield (Value 21 tells the game that you have a piece of armor equipped) 27-28: Initial Armor (Value 21 tells the game that you have a piece of armor equipped) 29-30: Initial Helmet(Value 21 tells the game that you have a piece of armor equipped) 31-32: Accessory Slot 1; If you unequip the item makes it unable to be equipped. (This is a natural bug) 33-34: Accessory Slot 2; If you unequip the item makes it unable to be equipped. (This is a natural bug) 35-43: Unknown; from what can be understood, it would be the attack, defense, vigor stats. (Unused) 44: Initial Guts 45: Initial Wisdom 46: Initial Luck 47-49: Initial EXP 4A-64: Unused There are three sets of characters in this data block. The first set is for the normal game, for the most part. The second set consists solely of Child Ryu and Child Bow. Adult Ryu (Maybe Adult Bow too) inherits his stats from Child Ryu. This is only worth noting if you want to change his starting stats. The third set is what I can only surmise are the team's stats during the title screen demos.
Stat gain tables
Stat Gain Tables: ---- Hex offset (LoROM Address) x05:71B0 - x05:5DEF ($C5:71B0 - $C5:5DEF) 4 bytes, split into 8 half-bytes in this order with a max increase of '15 (F)' per stat: Byte 1: HP, AP Byte 2: Strength, Stamina Byte 3: Unused, Agility Byte 4: Wisdom, Luck Almost every character seems to have extra level gains for levels they don't join at. These are not used at all due to the initial data. <br/>Also, it seems Bleu's stats uses the Monster Table as her level up data so she doesn't have her 'own' to modify without some serious stat table moving. Guts gain upon level is consistently the same for every level up. Each PC's gain starts at: x01:8FE5 ($81:8FE5)
Enemy stats: 59000-5A8FF Bytes 1-8: Name 9-10: Hit points 11-12: AP 13: Luck 14-15: Attack 16-17: Defense 18-19: Agility 20: Drop rate??? 21-22: Experience 23-24: Zenny 25: Item set 26-32: Unknown
For detailed information on how drop rates and item sets work, check out Ben Siron's handbook that explains many of the game's mechanics: link
Spell gains table
Pointers: 5AA00-5AA011 5AA12-5AADE Pairs of bytes. First is for level the spell is gained on, the second is the spell gained. 00 terminates.