Blacky is an Umbreon and a member of Auroz's guild, Team Illusion.
Blacky tends to act as the voice of wisdom in the guild. He tends to show few emotions, but he is completely capable of feeling them. He does get pissed off when people don't listen to him.
He handles important things such as finances and what missions the guild should do. He treats Auroz like a younger sibling instead of a friend and boss, and will occasionally mentor the Zorua in the ways of Dark types.
Pic by Sparkythechu!
Link
Irbis
What is Team Illusion?