The Fathomless Mastery is the third full-length album by Swedish death metal band Bloodbath, released on 6 October 2008 via Peaceville. It is the band's last studio album to feature vocalist Mikael Åkerfeldt and the first to feature lead guitarist Per Eriksson.[7] A video was made for "Hades Rising", directed by Owe Lingwall and shot on location in Vallentuna, near Stockholm.[8] The album peaked at No. 45 on the Heatseekers Chart in the US on release.[9]
The album was reissued in 2011, bundled together with the tracks from the Unblessing the Purity EP released in 2008.[10]
Former Scar Symmetry vocalist Christian Älvestam performed guest vocals on the sixth track, "Iesous".
The outro of the final track, "Wretched Human Mirror", features samples from the movie I Am Legend.[11]