Oluwatosin Ayoyinka Olumide Abasi (born January 7, 1983), is an American musician, best known as the founder and lead guitarist of the instrumental progressive metal band Animals as Leaders.

Tosin said in an interview, "My mom definitely represents more of the traditional immigrant mentality of education and conventional channels being way more important than a creative endeavor".

Javier Reyes and Navene Koperweis were enlisted on rhythm guitar and drums, respectively, after the completion of the album, turning the project into a full touring band.

[5] He also toured with the band Born of Osiris as a stand-in guitarist for former member Matt Pantelis whilst they were auditioning for a permanent replacement.

In 2011, Tosin started putting together material for a new band, T.R.A.M., consisting of his Animals As Leaders bandmate Javier Reyes, Suicidal Tendencies drummer Eric Moore, and former The Mars Volta wind instrumentalist Adrián Terrazas-González.

[8][9] In July 2014, Tosin appeared in the first episode of Guitar Power, a web-series sponsored by D'Addario String and Rolling Stone Magazine.

[10] In April and May 2016, Abasi joined fellow guitarists Nuno Bettencourt, Yngwie Malmsteen, Steve Vai, and Zakk Wylde, as part of the Generation Axe tour.

[15] In 2017, after leaving Ibanez Guitars,[16] Abasi wanted to expand on his design and include features such as locking tuners and 6 string options.

Notably, Abasi's collection reached into the hundreds, though many were sold off in 2020;[19] as such, this list focuses primarily on the entries of particular, which have either been seen at workshops, on tour, social media videos, or were used in recording.

At least, the original Ibanez prototypes boasted a "teardrop" neck profile, in contrast to the more common C- and D-shaped profiles (and Ibanez's Wizard necks, which near a D-shape, though are much flatter and complement the difficulties that come with common hand motions on extended range guitars), fanned frets/ multi-scale neck, which are designed to complement the hand contortions required for fingering chords and larger stretches in addition to improving tonality, feel, and timbre for each string individually, and tighter string placement (id est, the gaps between the strings are smaller).

The Kaizen is a multi-scale 6- or 7-string guitar with an “infinity radius” fingerboard and Heat Treated humbuckers, and an angular body designed by Abasi for ergonomic comfort.

The first two entries to this list are particularly interesting: used in at least "Physical Education" from The Joy of Motion and some of Weightless, while these are both 8-string'ed guitars, they feature a modified neck and fretboard that allows for two "negative frets" for the lowest strings.

For most of the 2010s, Fractal Audio's AXE-FX II was central to his signal chain, though the final third of the decade saw him swap to leaning primarily on analog effects and amplifiers.

His favored guitarists, musicians and bands include Steve Vai, Allan Holdsworth, Fredrik Thordendal of Meshuggah, Thom Yorke of Radiohead, Aphex Twin, Squarepusher, Mike Einziger of Incubus, and Dream Theater.