I wrote some stuff about Cagnazzo about his shell mode.
http://slickproductions.org/forum/index.php?topic=544.msg4314#msg4314I should've tried to clarify this better.
3 is the defensive value of the index that the stats are based off of.
It's not the actual index. To be frank, I think defense is actually set (the value of 3), but the post wasn't about that.
Some background:
There is an index of data that is used to set the parameters of monster attributes. There are 3 bytes each I think.
These are used for assigning three aspects of the monsters. Attack, Defense, and Magic Defense.
For example, let's use the Kainazzo (Cagnazzo) in FF2US v1.0 data through an FF4 editor:
Attack: 0x16 = 3x44 @ 99%
Defense: 0x77 = 2x2 @ 50%
Magic Def: 0xDA = 10x48 @ 50%
1st byte = Multiplier
2nd byte = Actual Value
3rd byte = Effectiveness
For Attack, this means, the monster can produce up to 3 hits, with 44 attack power, with an accuracy of 99%
For Defense, this means, the monster can evade up to 2 hits, with 2 defense, with an evasion rate of 50%.
Note: Evasion is NOT factored in unless you use a script to SET the defense. 255 Defense = immune to all physical attacks (doesn't include Throw since it isn't a physical attack, Jump and Power however are) Monsters in general have NO evasion.
For Magic D, this means, the monster can magically evade up to 10 hits, with 48 magic defense, with a magic evasion rate of 50%
Note: Magic evasion is never factored in I believe. 255 Magic Defense = immune to all magic. IIRC, Magic evasion is never a factor for monsters, so it's an irrelevant stat.
The point of the info was that in some of the bugged versions of FF4A, the defensive set in the script is not done or is executed/enforced correctly.
In the script (when going into shell mode - the mode that causes the monster to heal itself), it sets defense to index 0x7A. This would produce a monster with the defense of evading @ most 3 hits, with 3 defense, and has a chance to evade @ 70%. If you have ever hit that side of the script with a low level Cecil, you will find him to do pitiful damage against Cagnazzo. The script works as intended as far as I can tell (unless you get Cecil to dish out 4 hits @ minimum).
Hopefully, that clears things up.

Clarification on the part of the script that causes the changes.