Rodimus was an elderly man who was loyal to Zelgadiss Graywords. Despite his apparent age, Rodimus appears to be a skilled fighter and manages to hold his own (with the help of Dilgear) against much younger fighters like Gourry Gabriev.

Despite Zelgadiss turning against Rezo the Red Priest, Rodimus chose to remain under the chimera's command, as he stated that their loyalty lied with Zelgadiss, not Rezo. After which, Zolf and Rodimus both joined the Slayers along with their master. They didn't remain on the team long, however, as soon afterwards, Rezo resurrected a fragment of the Demon King. Zolf mistakenly cast a Dragon Slave on Shabranidgu, hoping it would be destroyed. However, he reflected the spell which killed Rodimus and Zolf.

(Source: KanzakaDex, edited)