There are Six different Hounds,Hell Hound Storm Hound,Frozen Hound,Blood Hound,Ghostly Hound and just a regular Hound. They scale in Size from Strongest to weakest,Hell Hound biggest, Hound smallest. Actually they all scale to the level of the player they just have different sizes and skins. They are permanite summons and will last until they die which will be fairly quickly at a low level. If you don't have enough magicka I'm sorry you will have to use god mode.
The six books of the hounds are found inside Jorrvaskr(Home of the Companions) in Whiterun just look around and you should beable to find with some of the storage in the corner.

UPDATE*
Adds a new hound to the game. The Phantom Hound. Made by request. The book is located in the same place as the previous books. The Phantom Hound is a decently sized purplish ghost hound.

Now adding in the Target Bow, which simply is a smaller sized longbow that does an epic 0 damage!!! I personaly love sending my hounds at targets using my bow, but, I practicly kill them..
So I made this bow so the hounds can have all the fun! Watch them as the chew away their next victim!

Download,endorse and comment!!!
You are welcome to give me advice aswell as new ideas.

P.S. I am currently working on another mod that allows you to have animal pets, Horker etc..
But, I can't figure out how to make them work!!!! If you now please comment so i can finish the mod and upload it:)