Spencer O'Brien (Earth-5875)

"I don't miss! I never miss!"

- - Blake O'Brien

Blake O'Brien is an Orbital Drop Shock Trooper in the 105th Shock Troops Division of the UNSC Marine Corps, who fought during the First Contact War. By April 2545, O'Brien was assigned to an ODST squad led by Master Sergeant Kalob Cortez aboard the UNSC Kronstadt.

Operation GREY VEIL
O'Brien and his Orbital Drop Shock Trooper team were assigned to participate in Operation GREY VEIL by Officer Lamar Faulkner. The operation consisted of assassinating a san'shyuum who was ready to oversee logistic operations on the Covenant colony Heian. Blake was assigned as the operation's backup sniper, which he felt was an insult to his skills, something that worsened when he discovered the main sniper was a SPARTAN-II, Cal-141.

The squad was deployed to Heian two hours later aboard their SOEIVs. O'Brien's pod crashed in a cliff upon landing, falling into a swamp pool. When it began to skin, it was taken out of the swampy waters by Cal, who pried the door and allowed O'Brien to escape. Despite this, Blake was unimpressed, only to be struck by the shocking news that one of his teammates, Mark Checkman, had died in Heian's atmosphere before he could even land.