Born as Ro'tin on the planet Ba'ku in the Briar Patch, Ru'afo was one of several of the young Ba'ku individuals who longed to explore the galaxy, needing advanced technology to accomplish his aspirations. His beliefs were in direct contradiction to the simpler ways of life the Ba'ku desired. When Ru'afo and his small group tried to takeover the Ba'ku village and were unsuccessful, they were exiled from the planet.

After years of being affected by the aging process, Ru'afo became obsessed with gaining revenge against his former people and was desperate to re-obtain longevity. Partnering with Starfleet admiral Matthew Dougherty, he attempted to extract the metaphasic radiation from the atmosphere of the Ba'ku planet in the hopes of reversing the aging process. His efforts were halted by the crew of the USS Enterprise-E and Ru'afo eventually died in the destruction of the Son'a collector. (Star Trek: Insurrection)

Irenicus has a lust for power - such an insatiable urge that he was kicked out of his city of birth for it and banished along with his half-sister Bodhi. Both of them are elves, although each go to different lengths to disguise it - Bodhi adopts vampirism and Jon either removes his ears or simply keeps his skull cap on at all times (it's never made clear). His banishment has done nothing to satiate his urges, only fuel his desire for revenge, and as the child of Bhaal you're the prime target for him to build his power.

His plan is carried through to fruition midway through the game where he literally steals your soul and augments his already formidable magic powers. He plans on using the power to incite a war between the Drow (dark elves) and Elves, and use the resulting chaos to steal the essence from the elven Tree of Life, becoming a god in the process.

After foiled in his plans a final time, Irenicus is swarmed by demons in hell and torn to pieces.