In Halo Reach for Xbox 360, there are several Avatar items you can unlock by performing certain tasks in game.
Carter’s Helmet – Clear a single Campaign mission on Legendary without dying
Emile’s Helmet – Earn a Bulltrue medal in either Multiplayer or Firefight Matchmaking
Jorge’s Helmet – Earn a Killtacular in Multiplayer Matchmaking
Jun’s Helmet – Kill 100 enemies in a row without dying in either the Campaign or Firefight
Kat’s Helmet – Avenge a teammate in Multiplayer Matchmaking
