The personality works this way:
[personality:name:minimum:median:maximum] values (0 is zero, it means that the creature has this trait as minimum, i.e. no pity/total pessimism/...; 100 is a maximum value) for the population. It changes the creatures... personalities. The details you see when you look at their thoughts.
Min/med/max determine the chance for each creature of this civilization to gain the value near "med" but with possible change up to "max" or down to "min".
Wiki is great.
List of traits:
http://www.dwarffortresswiki.net/index.php/Personality
There're few problems with your batman:
1) MAIN THING: you can't use 2 letters in the place of one. Try to type on your keyboard 2 letters the way that they will be placed in the place of 1 letter. I speak of TILE. Only one letter, 'BM' is wrong.
2) You don't need INTELLIGENT and CAN_SPEAK+CAN_LEARN together. INTELLIGENT has CAN_SPEAK, CAN_LEARN and CAN_CIV together.
3) Your creature doesn't have biome tags, but has LARGE_ROAMING and LARGE_PREDATOR which won't work because it won't spawn (no biome tags)
4) It has no body thus no body parts -> it cannot wear/wield items/armor/weapons. You may want to add a body.
5) There's already a batman creature in the game with exact the same tag : BATMAN. They will conflict.
If you need any answers, just ask.
Also consider to look here: http://www.dwarffortresswiki.net/index.php/Creature_tokens
P.S. Yes, you get immigrants for any playable race.
[ April 26, 2008: Message edited by: Deon ]