Sorry manaseed, would have responded sooner but ive been at a friends house since yesterday at a party.
Like he said would have been better posting on the mod page, but ill answer it anyway because im nice.
You get different pets at different levels, also you get one new skill, spell or ability every level after you talk to the Shadow Master for the first time.
You get the wolf at level 8, (Next stage of the quest if you wondered starts at level 10) panther at level 11, (Last stage of the quest starts when you get to level 17) and you get the bear at level 18.
Its more of an incentive to keep leveling as every level until 25 (Possibly soon 30 but im having trouble thinking up new spells)
Any more questions feel free to ask in this thread, ill make sure to answer them