Over two years, Townsend wrote over 60 songs, and found that they fit into "four distinct styles". In March 2009, Townsend announced his plans for a four-album series called Devin Townsend Project, with the goal of clarifying his musical identity and being "accountable" for the persona he projects to the public. The project's concept includes a different "theme" and a different group of musicians on each album.
Ki, the first album of the Devin Townsend Project tetralogy was written to "set the stage" for the subsequent albums. Townsend channelled his new-found control and sobriety into Ki, a "tense, quiet" album, which contrasts with much of the music he had been known for. Additional female vocals were provided by Ché Aimee Dorval (Casualties of Cool). Ki was released in May 2009.
The second entry, a "commercial, yet heavy" album called Addicted, was released in November 2009 and features lead vocals from Townsend and Dutch singer Anneke van Giersbergen. Brian "Beav" Waddell was recruited from the Devin Townsend Band to play bass.
From 2009, Townsend worked on a long-running album project called Z, a sequel to the album Ziltoid the Omniscient (2007). Originally in 2012, he teased he "may have just written the heaviest thing (he's) ever done" for the album, and stated there might a surprising lack of Ziltoid himself appearing on the album. However, in August 2013, a London-based radio station, TeamRock Radio, aired the first episode of Ziltoid Radio, a satirical radio show hosted solely by Ziltoid, this being one element of the Z project. Townsend also discussed a "ZTV" or "Ziltoid TV" to precede the album. Townsend later stated he found the project hard to schedule and work with amidst touring and writing, stating "it takes a lot of effort" to keep the content and its tongue-in-cheek humour entertaining.
After returning to public view in 2009, Townsend began endorsing Peavey, and later released a PXD Devin Townsend signature model, essentially a Flying V-style 7-string baritone guitar with an EMG 81-7 pickup and a 7-string EMG SA single coil pickup in the neck position. Peavey also made Townsend a number of custom 7-strings, including one with a single EMG 81-7 pickup that is used for playing most of the material on Ziltoid The Omniscient. Aside from his signature model, Townsend also utilizes two custom 6-string Predator models made by Peavey; one with a natural flame-top finish and the DTP logo on the 12th fret, and one in a black finish with a Floyd Rose vibrato unit (for Open C and Open B tuning, respectively).