Dosu-Roku was Akira Fudo's former bully turned freind from Devilman. He showed up a whole bunch of times throughout the manga, at first being a potential rapist towards Miki Makimura, he tone later softend till he was best of buds with Akira. He shows up in a few Neo Devilman stories and in AMON he becomes a devilman for a short while before being killed. In Grimoire he is killed by Aleda. He shows up in the birth, vs cyborg 009 and vs Hades as well. In Devilman:The Birth he shows up at the start and f's with Akira to try to slag a bunny after slagging the other bunnies. But Akira's resolve impresses the thugs and they let him go.
In Devilman:The Birth he was voiced by sukekiyo kameyama who was also dr ichiro in zatch bell, Police Chief Muraki Uramura in rurouni kenshin, hachi in summer wars, lao in (The) Legend of the Galactic Heroes and weird enough; dr mamushi inj cyborg 009 the cyborg soldier