Olympia Vale (Halo 5)
Halo 5 aims to be a big universe changing game for the franchise, and nowhere is that more apparent than with Fireteam Osiris. A mixture of four different branches of the Human military, Osiris is comprised of characters found only in the expanded universe stuff.
Fans are already familiar with Nathan Fillion’s ODST turned Spartan Buck, Locke was the star of the Nightfall miniseries, Tanaka first made her appearance in the Halo comics, and Vale first showed up in the novel Hunters in the Dark. Vale’s job in Osiris is to translate the Elite language, but she’s more than just a walking Wikipedia. Her brains and curiosity in the in-game dialogue end up helping Osiris figure just what the hell is going on in the game before everyone else does. Her skills in and out of battle help humanity figure out the goal of the Guardians. If this gaming juggernaut is going to bring more expanded universe stuff going forward, Vale’s a great example of how to do it.