Beowulf

ONI Artificial Intelligence construct. Beowulf was the attaché to Admiral Micheal Stanforth and the UNSC navy. He was present during the Spartans original briefing about the Covenant.

He was later assigned to guard the UNSC personnel and planning database. He knew Cortana well, and knew that she was trouble. When she would try to get into the system, he would block her entrance.

He was thorough, methodical, and paranoid. However, compared to Cortana's code cracking skills, he might as well be an accounting program. He was incapable of learning because he was a "dumb" AI.

His hologram form was that of a man wearing a hooded cloak.

Also, though not proven, Beowulf was believed to be aboard the Pillar of Autumn as the second AI. Though not proven, it is listed as BW, possibly Beowulf