Credited either as オオノ, 大野 正輝 (Oono Masaki) or M. OHNO, there is almost zero information about this good man, but we owe all the drumming in Nageki Shito and almost all of the drumming in Da'vid/shito:aL to him. For some reason he always kept the support member status.
Oono's first musical work was in the band 業 (Karma), along with Rietto, Eruze and Pietoro (who were called Yoshihiko, Aoi and Touya, respectively at the time). Oono also had support drummer status during Karma.
It seems Oono is still playing drums in various jazz bands nowdays.