Dark Corners Of The Earth (Hellsing X Hellboy)

When the world is threatened with indescribable madness at the hands of a cult dedicated to the Old Ones, the B.P.R.D. and the Hellsing Organization must send their top agents to end this threat: Hellboy and Alucard. The two soon find themselves on a journey of madness the likes of which that will test both the sanity of both the Demon from Hell and the Lord of Vampires.
Hellsing belongs to Kouta Hirano
Hellboy belongs to Dark Horse Comics