The good folks over at Lineage II have provided us with this dev diary concerning the pet system enhancements that are coming with the Hellbound expansion due later this month.

Lineage II players absolutely love their pets. They are useful companions in the lands of Aden, able to conduct a varied series of attacks, use special skills, and more, all in aid of the player. In addition, pets can go through a series of evolutions, earning new abilities and becoming much more powerful with each step. Pets only have a few downsides—they lose some experience upon death and must consume a quantity of food before they grow hungry and ineffective, but overall to players they are a boon.

Since Chronicle 2 we've been slowly improving the pet system, added a new type of pet here, a new layer of evolution there. With the release of Hellbound we've expanded the pet system even more, with benefits that will help most players in one way or another. Those that have a Wolf as a pet can evolve it normally into a Great Wolf once it gets to level 55, and then further evolve it into a Fenrir if it’s above level 70. The Fenrir is the third evolutionary stage of the basic Wolf and offers many powerful skills and special attacks. Players can upgrade their pets through the Pet Manager NPCs in most towns; these Pet Managers also have a pet raising guide and other useful tips they’d be more than willing to share.

Read more here.