An Intergalactic Valedictory

What if in the movies, when humanity is faced against a galactic horde, they are never able to release their final weapon. That's the story of this one weapon. He was made but didn't actually turn on until it was thousands of years too late.
This is his story of learning what he truly is, traveling the cosmos, and bidding fond farewells wherever he goes.....most places he goes.....some.