Ensign Masaro (portrayed by Josh Holt) was a minor character in Star Trek: Enterprise. He was a junior engineer aboard the Enterprise NX-01 throughout the series, appearing in the background in several episodes. What no one among the crew knew was that Masaro was secretly a member of Terra Prime, an extremist group that sought to put an end to all diplomatic relations between Earth and the alien races Starfleet had encountered.
In the Season 4 episode "Terra Prime", it was revealed that Masaro had acquired genetic material from Commanders T'Pol and Trip Tucker, sending it to John Frederick Paxton shortly after the Xindi crisis. Paxton used these samples to clone a Vulcan-Human hybrid infant which he would use to rally supporters for his cause.
When Captain Archer decided to lead a small team to infiltrate Paxton's base on Mars, Masaro covertly sabotaged the team's shuttlepod, nearly causing them to crash. Later, when it was discovered that Masaro was the saboteur, he confronted Captain Archer with a phase-pistol. Apologizing to Archer for his actions, Masaro put the phase-pistol to his own head and committed suicide.