Only One Actor Was Killed By Terminator, Xenomorph & Predator (And No, It's Not Sean Bean)
In fact, it is late Bill Paxton, who would have been 67 this year.
And yes, he was the only actor in the history of Hollywood who got the honor of getting killed by those three iconic monsters, though even film buffs might be hard-pressed to remember who his characters were, and under what circumstances they have perished.
That's because the first "death" involved a very minor character, effectively an extra, and probably only a very few can associate that character with a specific actor without googling Paxton's filmography.
He played the punk leader, who got killed at the very beginning of the original Terminator, when the titular cyborg from the future first demonstrated how deadly it can be (despite being butt naked).
However insignificant that role was, it apparently made James Cameron notice Paxton.
So, Paxton got the role of Private Hudson in Aliens, which earned him a Saturn Award for the Best Supporting Actor, and the distinction of becoming a victim of another famous killing machine from movies, this time a figurative one – his character got dragged away by xenomorphs on LV-426, resulting in his death.
Private Hudson actually was one of Paxton's most memorable roles.
But the role which involved his character dying to a Predator was almost as obscure as that of the nameless punk leader, not because the role was as minor, but because the movie ended up not as popular as Terminator.
Unlike Aliens, Predator 2 failed to become a worthy sequel to a classic movie. And though it can be argued that the movie was still quite good, by now it got largely forgotten.
In Predator 2, Bill Paxton played Detective Lambert, a subordinate member of the main character's police team, and Lambert's role often was that of comic relief.
However, his death still managed to be pretty heroic – Lambert clearly stood no chance against the extraterrestrial monster, but fought anyway, and before getting splattered he at least managed to produce a memorable last line: "Let's dance!"
So, as you can see, a career of playing mostly supporting and secondary roles, as Paxton did in his earlier years, can still be remarkable.