Seta Noriyasu

Seta is a Tokyo University professor and archaeologist who graduated from the university and made it in after being a ronin for three years. Spending much of his time touring the world on expeditions, Seta most desires to find the whereabouts of a lost turtle civilization. He's a skilled martial artist and former tutor  to  Naru Narusegawa, oblivious to the fact his former pupil grew a crush on him. He's also the adoptive father of American girl   Sarah McDougal choosing to raise her following the death of her mother, who was his former lover and assistant.

 
Despite these impressive traits, Seta isn't without his faults. Like Keitaro, Seta has trouble with a woman he cares for him -  Haruka Urashima. She also has an attraction to Seta that the guy is oblivious to. Haruka was friends with Seta and Sarah's mother in college and the three used to travel together on expeditions. Much like Naru does to Keitaro, Haruka would also pummel Seta if he was clueless about any hints that there were to her attraction to him. Seta is also a terrible driver as many of his reappearances in the series come from him getting his van in an accident and appearing out of the wreckage in his usual composed attire, oblivious to his face being covered in blood.

  Keitaro Urashima looks up to him and eventually winds up being exactly like him.