Jinnai, Katsuhiko

陣内克彦

Katsuhiko Jinnai (陣内克彦 Jinnai Katsuhiko) secures victory in the Student Body Presidential election by pledging student government funds to campus clubs and organizations that cast their votes for him.
When Makoto learns of this and arrangements are made for him to testify against Jinnai (who is referred to as "Jinnai" by everyone except his sister), the egocentric, power-hungry, and soon-to-be-impeached Student Body President tries to sabotage the process by attacking Makoto. His intention is to keep Makoto restrained until a technicality in the bylaws prevents his removal from office. However, before he can carry out his plan, he is transported to El-Hazard, where he encounters the Bugrom, a race of human-sized insectoid beings ruled by Queen Diva.
The power Jinnai gains from the trip is the ability to communicate with the Bugrom, which allows him to become their military commander under their belief that he is the messenger from God sent to lead the Bugrom to victory. As a skilled tactician, he reorganizes the Bugrom forces into an effective army and nearly conquers El-Hazard.
Although Jinnai is a power-hungry egomaniac, he retains some level of humanity. When Galus attempts to stop Makoto and the others from halting the Eye of God's apocalyptic malfunction, Jinnai takes the leader of the Phantom Tribe by surprise with the help of a Bugrom soldier. Although Jinnai effectively rescues Makoto and Nanami, he does so primarily because a "true ruler doesn't destroy the land he wishes to conquer." Jinnai has a very distinctive laugh.
Jinnai suffers from an obsession with Makoto that borders on the psychotic. Throughout both series, he consistently blames Makoto for essentially every failure and disappointment he experiences. His perception of his own history is a montage of misfortune, with Makoto as the chief architect. Though generally megalomaniacal, one of his primary motivations for gaining power is to subsequently acquire the ability to best, or even kill, Makoto.
Jinnai in The Wanderers
Jinnai does not change much in the transition from the OVA to the TV series, either, but he seems to treat Ifurita with more care. Although he is threatened with impeachment from his position as Student Body President at the beginning of the series and Makoto plays no direct role in the trial, he is paranoid that Makoto will replace him as president once he is removed from office.
Additionally, Jinnai reveals a softer side at the end of the series, showing a certain fatherly affection towards Ifurita after she stops the Eye of God from plowing into Roshtaria. ~From Wikipedia