There are multiple artists that go by the name oni.
1) ONI is a croatian hip-hop group. Members are Scriptor, Jantar, Kali (MC's), KolAK47 (producer) and DJ Noki Nole. Their first album titled Lajtmotiv came out in 2015.
2) Akinyeme Olagdeji Odawali Oni Orison is a rapper who made sophomoric slump with Beatmonger's productions. The two met while going to the University of Michigan.
3) A Brutal Death Metal band from Adelaide, South Australia.
4) ONI is a venezuelan Post-Metal band too, from Caracas South-East side, in the State of Miranda, Venezuela.
5) A young and promising DJ from Finland. Plays mostly Happyhardcore and Freeform.
6) A band from Široki Brijeg/Mostar in Bosnia and Herzegovina
7) A female artist from Bangladesh.
8) ONI is a Icelandic Sludge Metal/Stoner Rock band hailing from Neskaupstaður, Iceland.