Guessing from the title of the series I think Tenchi's the main character. Though having him in the show contradicts the title of the show(No Need for Tenchi). Since he was young his granfather has been teaching how to fight so that one day he can send him to Jurai to take his place at the throne.

One day Tenchi life changed forever, a day he sorta regrets. As, he was searching through his grandfather's things looking for the key to the Masaki Shrine his grandfather catches him and after a little scene Tenchi accidentally got the key. Once in the Masaki Shrine he finds the Tenchi-ken and accidentally releases the demon Ryoko.This event lead to chain of even more events which leads to Tenchi being surrounded by 5 women.

Tenchi some how draws the interest of all of these women. He does like them all and cares for them. He is willing to risk his life so that no harm comes to them. Though he can protect them he is a bit shy about making any moves(if he wants to). If he wanted he could have any of them but either he's not ready, interested, or too scared to start anything.

A few times throughout the OVA Tenchi begins thinking and remembering about his mother. He was lonely for a big part of his life up to when he mets the girls. In one scene Ryoko wore his mothers robe and it reminded him strongly of his mother, until Ryyoko accidently ripped it which pissed him off.