Matthew was a normal child when the end of the world happened. Darkness erupted from the Earth, casting demons onto the people of Earth. Matthew should have died when the demons poisoned his soul with darkness, but he survived.
He fought for humanity for years alongside others of his kind.
Humanity in return, cast him out and into the void with no hope of returning home.
Now Matthew will remain in the realm of Equestria for the rest of his days.
With some luck, he might just find the happiness he has always longed for.
Some slight swearing, but kept to a minimal.