Fan artist Vynthallas has put together some really fun illustrations of Night Angel characters, including this one of Kylar Stern with the black ka’kari:
Go HERE to see more Night Angel illustrations!
Update: This fan art is a composition of various other pieces. Vynthallas explicitly credits it on his DeviantArt page: “Body (Witcher), Face (Final Fantasy), some little various parts from Assassin’s Creed, and the Ka’kari I took off the official Homepage from Brent Weeks (Artist: “Ninjaman Todd“)” — We apologize for not including the list here as well. (Thank you to Patrick, in the comments, for the links!)