Ares is a werehyena and a guard at the Circus of the Damned. He is ex-military, and usually partners with Bram, although they aren't very similar beyond the military bearing. Ares is killed in Affliction.
Ares has yellow hair that he keeps buzzed military-short. In Bullet he still has a golden tan from somewhere hot and dry.
Ares used to be part of a group of snipers and their spotters who specialized in shapeshifter targets, until a werehyena figured out their tactics and got a drop on them. Ares got a medical discharge once he tested positive for lycanthropy.
Ares joins Narcissus's Clan before Bullet, and becomes one of the guards employed by Jean-Claude. We learn that Ares has a tendency to be snotty, and doesn't have Anita's endurance.
In Kiss the Dead ...
In Affliction Ares is one of the guards chosen to accompany Anita, Nathaniel, and Micah to see Micah's dying father. Ares's military background helps him get along with the various flavors of cops guarding Sheriff Callahan. He is allowed to participate in a hunt for some missing people thanks to his scout sniper background, and helps to defend cops and Nathaniel against zombies and rotting vampires. He gets bit in the process and catches the rotting disease, and Anita talks him into the helicopter for the worst injured.
Unfortunately Morte D'Amour has hyena as his animal to call, and the bite opens Ares to his influence. He shifts in the chopper, forcing it down, and kills and maims several people onboard. Once the chopper is down Ares charges a family, and Anita is forced to shoot him using the sniper skills Ares himself has been training her for. The first shot isn't fatal and is enough to distract him from his prey, but when he tries to escape, Anita takes him down for good. His loss as one of the guards is still felt several books over.