Right hand - MkVI Iron man
Left hand - Zartan
Nozzles - Marauder silencers
Back pipes - PotF2 Sandtrooper rifle barrels/ twist ties
The rest - MU black Spidey
An unknown race from beyond the stars, the Aliens were the guardians of the malevolant Ogdru Jahad. Their mission to ensure the beasts of the apocolypse are never released has spanned millenia.
This particular Alien was sent to Earth to destroy Hellboy, preventing his immenint fall from grace and eventual decline into evil, bringing about the end of the world.
A shapeshifter who had assumed human form for many years, the Alien had secretly observed Hellboy from infancy and grown to respect his heroicism. When the time came for Alien to kill Hellboy, he found he could not do it, instead revealing the true nature of Hellboy's past, and his future.