###Wolf as NPC
Wolf as NPC
Accepting you have ruled the fighter’s successful Animal Handling skill check will make the wolf a friendly ally, you now have a four-legged NPC to role-play. Treat it as any other:
Image how a character or monster…would react to the adventurers. Consider what it cares about. Does it have any ideals, flaws, or bonds? ... Strive for responses and actions that introduce twists into the game.
DM Guide 245
Just because the wolf is friendly to the fighter doesn’t mean it will do anything in particular the party wants. What it does is entirely up to you as DM, based on what kind of wolf you invent it to be.
Take into account the wolf’s low intelligence, its inability to understand language, its alignment and disposition. Consider the fact that one of the characters has handled the creature — it might have any attitude towards other members of the party.
###Don’t “give away” class powers
Don’t “give away” class powers
There are no specific rules on how a tamed beast would behave differently than an untamed one. However, there are rules on controlling animals, that are Ranger and Druid powers.
Familiarize yourself with these powers, and make sure that this fighter’s one good roll does not give him a power that rivals the ranger or druid powers. (You wouldn’t give someone the ability to cast spells just because they made one good Arcana roll.)