From Seven Seas:
An ancient alien civilization once hid artifacts of immense power across the Earth, and now the world’s governments will stop at nothing to seize those relics for their own nefarious purposes. Only the ARCAM corporation stands against them, whose special agents, the Spriggan, are the world’s last line of defense against the alien doomsday weapons. Equipped with experimental armor that grants him unmatched strength, Ominae Yu is Spriggans’ ace operator, sent to avert catastrophes around the world.

Note: The First Mission prologue and Gold Rush epilogue are included in all reprints but not the original tankobon release.