The Agent of Malekith collection contains two premium cosmetics for Kerillian: the Mask of the Shadow-Slayer hat and Naggarond Backstabber skin.

The cosmetics can be used on Kerillian’s Shade career.

About the cosmetics:

Mask of the Shadow-Slayer - Hat
Garb worn by the Shades of the Ashen Hills, whose footfalls leave no sound, and whose blades slice through armour as cleanly as skin.

Naggarond Backstabber - Skin
Assassin's garb, worn by the particularly untrustworthy (distinctions matter in Naggaroth).