Obsidian Chamber - Ein Platz Am Kamin

Obsidian Shrine - Bloodshed Under The Black Star

Obsidian Shrine - Dereliction Of Divinity

Obsidian Tongue - The Stone Heart

Obsidyen - Litany Of Iah

Occulta Veritas - Irreducible Fear Of The Sublime

Odio Deus - Spiritual Syphilis

Odyrmos - Odyrmos

Ofermod Black Altar Acherontass - Drakonian Elitism

Ofermod - Ofermodian Litanies

Oferwintran - It Often Befalls Those

Offernat - Where Nothing Grows

Ofnus - Valediction

Old Forest - Sutwyke

Olde Throne - An Gorta Mor

Olde Throne - In the Land of Ghosts

Olhava - Reborn

OLiM - A Mighty Disposition

Omega Infinity - The Anticurrent

On Graves - The Grotesque

Ondfodt - Det Osterbottniska Morkret

One Master - The Names of Power

One With the Riverbed - Succumb

Ontborg - Following the Steps of Damnation

Ophanim - Taempelsklaeng

Opus Irae - Into the Endless Night

Orcus Patera - Die Seuche

Ordalie - Indifferent Universe

Order of the Nameless Ones - Utter To Me The Word Of Wrath

Orgrel - The Oath Of The Black Wolf

Oriska - Oriska

Orm - Intet * Altet

Ornaemental Shine - Deima Panikon

Ossilegium - The Gods Below

Othismos - Sottrazione

Our Loss Is Total - I

Outlaw - Reaching Beyond Assiah

Overlord - The Chambers Of Hell

Owls Woods Graves - Secret Spies of the Horned Patrician