I served you for so long, but you let your research be frozen so easily, and the honor and renown we were supposed to get all went away… If I didn’t get at least some money, then it was a waste of my time!Samuel Abraham to David Shield in Two Heroes
Sam is an older, heavier man with short blond hair and blue eyes, which are normally kept closed.
He wears typical business attire, a suit and tie outfit with slacks, suspenders and shoes.
Sam appears to be a goodhearted scientist at first, aiding David throughout his career. However, Sam believes his work warrants a reward and desperation lead him to betray David and throw in with the criminals.
In spite of the betrayal, he was surprised David still defended him.
Both scientists attend the I-Expo's reception party, but its invaded by Wolfram's Crew. David and Sam are both seemingly taken hostage and escorted to the Storage Room. There, David and Sam work together to unlock the slot holding the Quirk Amplification Device. A device that the two scientists developed in the past but got confiscated by I-Island's higher-ups.
David and Sam staged this villain attack to get the Quirk Amplifier back. David believed they hired fake villains, but Melissa catches up to them thanks to Izuku Midoriya and his friends fighting their way through the tower. It turns out that Sam hired real villains and betrayed David's trust to ensure he'd be properly compensated for all his research.
Wolfram appears and decides to keep his end of their deal by shooting Sam. David jumps in the way of the bullet, saving Sam's life. Surprised, Sam asked David why he did so.