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 87C and ends at D3B (Assuming no header). Each entry is 64 bytes long. Layout:

1-4: Name

5-6: Unknown, 00 00 for everyone

7: Character's number

8: Initial level

9-10: Unknown

11: Initial HP

12: Initial HP, 00 for all; allows numbers bigger than 255

13-14: Unknown; always the same as initial AP.

15: Initial AP

16: Initial AP, 00 for all; allows numbers bigger than 255

17: Character portrait/sprite modifier; 00 for everyone

18: Initial Strength

19: Initial Stamina

20: Initial Agility

21: Initial Agility, 00 for all; allows numbers bigger than 255.

22: Initial Condition

23: Initial Weapon

24: Always 11 when above is used. Doesn't seem to do anything...

25: Initial Shield

26: Always 21 when above is used. Doesn't seem to do anything...

27: Initial Armor

28: Always 21 when above is used. Doesn't seem to do anything...

29: Initial Helmet

30: Always 21 when above is used. Doesn't seem to do anything...

31: Accessory Slot 1; unequipping the item makes it unable to be equipped; item might not function correctly

32: Unknown; Could be related to above

33: Accessory Slot 2; unequipping the item makes it unable to be equipped; item might not function correctly

34: Unknown; Could be related to above

35-43: Unknown

44: Initial Guts

45: Initial Wisdom

46: Initial Luck

47-64: Unknown

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 information

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.