Hi,
some creatures lean to the good or the bad side (Tiger leans bad, cow leans good, Ape is neutral). so it's possible that if oyu have the Tiger that it naturally goes evil.
that doesn't mean you can't train him to be good tho. the way to do it is to use the leash of compassion and then reward the creature whenever she does something good (and punish her when she does something bad). i think the creature won't change it's affiliation if she is not punished/rewarded for an action!
so if you want her to be good, it's not enough to tie her to something with the good leash, you also have to reward her after she's done something good (or punish her if she does something bad).
hope this helps!
cheers,