Depending on your character's class and average gear level, you may want to bring a friend to help you kill the rare-elite. (Actually, bring a friend anyway because the density of mobs in the area is annoying.) The fel wolf has three abilities - an interruptible fear, a DoT, and a ground AoE. If you keep the fear interrupted or break its effect before you run too far away from the fel wolf, he never uses the ground AoE. I was able to solo Ceraxas as a ilvl 666 fire mage with 4p tier bonus and ilvl 690 pre-legendary ring. Time Warp, Mirror Images, Ice Barrier, and Ice Block let me solo with relative ease.
Note: Ceraxas is an actual rare - you'll have to camp or depend on other players calling the mob out in general chat. (If you're lucky, maybe someone will even form a cross-realm group.)
Killing Ceraxas will cause an Abandoned Fel Pup to spawn in the back of the small area. He offers the quest A Fel Puppy Of My Own which awards Fel Pup.
Do not expect the sell price to make it to the live version of the game. Although the 1,000 gold sell value is in line with other garrison blueprints, this blueprint is provided by a quest giver - meaning that I can sell the blueprint, abandon the quest, reacquire the quest, and repeat.