D.O.S. (Deadly Operating System) is a 6-track album released under Azrael-II. It is the first album to be released under the alias since Azrael's 2014 redesign.
- Intro (1:40) (lyrics)
- Powerhaus 2014 (4:26)
- Lyssa Fell (5:32)
- Octabrain (feat. RQ) (4:55)
- MiKU MUST DiE (5:04) (lyrics)
- Lyssa Fell VIP (5:43)
- MiKU MUST DiE (NegaRen RMX) (5:06) (Physical release, pre-order, and Patreon exclusive)
- DJ Snaggletoof - D.O.S. CD Megamix (37:02) (Physical release & Patreon exclusive)
Megamix track listing Edit
- Tune Out
- Dead By Dawn
- The Killer Returns
- Off With Her Head
- Rock You
- Pokamen Party
- Digimon (Digital World)
- Never Fade (Azrael-II RMX)
Release notes Edit
- The album was posted on Bandcamp on July 3rd, 2014, with an option to pre-order the album. At this time, a placeholder image was used as the album art and the sixth track, Lyssa Fell VIP, was not listed. On September 6, the album was made available to Ren's Patreon supporters and the Bandcamp page was updated with the final artwork and the 6th track.
- A seventh track, a NegaRen remix of MiKU MUST DiE, was released as an exclusive track for people who bought the album during its pre-order stage, and for $4 or more Patreon supporters. It was later also included on the physical release.
- The physical release of the album included "a 14 track megamix by DJ Snaggletoof of classic Azrael tracks."
- The title is a reference to Disk Operating Systems, or DOS. Artwork used in previews and track covers reflect this.
- MiKU MUST DiE is named after the popular Vocaloid character Hatsune Miku. She could be seen running in the track's original preview video. The track name may also be a reference to MikuMikuDance, an animation software used to create Vocaloid videos.
- Octabrain is named after a type of enemy in Duke Nukem 3D, and the track samples sounds from the game. 
- Lyssa Fell is named after the Greek goddess Lyssa, the goddess of mad rage, frenzy and rabies.