Masaro

From Memory Alpha, the free Star Trek reference

Ensign Masaro was a Human operations division Earth Starfleet crewmember serving aboard Enterprise NX-01 under Captain Jonathan Archer during the 2150s.

He was aboard Enterprise during its mission into the Delphic Expanse, implying that he joined the crew no later than mid-2153. Masaro was one of the many injured personnel under the care of Phlox after the devastating Xindi attack on the ship which occurred in the Azati system in early 2154. (ENT: "Damage")

Along with the rest of the surviving Enterprise crew that returned from the Expanse, Masaro was regarded as a hero. (ENT: "Home") However, in early 2155 his knowledge of the ship and its personnel was useful to a group known as Terra Prime. When Masaro became affiliated with the group is unclear, but his role as an engineer aboard Enterprise allowed him great access to the ship.

Soon after Terra Prime's attempts to disrupt the Coalition of Planets conference, it was learned that he was the individual responsible for sabotaging Shuttlepod 1.

Shortly after his role was discovered, he confronted Captain Archer with a phase pistol, apologizing to him before committing suicide. (ENT: "Terra Prime")