Ultraman: Every Day, I Want to Kill Dark Tiga

No heroine + sister complex + dead set on killing Diga + native

The protagonist is a gentleman who can control his emotions. He is polite and does not blindly resort to violence. He knows right from wrong and whom he should fight, and he rarely drags innocent people into things.

He is not exactly a bad person, but he is not exactly a good person either.

Kanas has always remembered that he has an enemy: Dark Diga.

He betrayed his friends and harmed Kanas's older sister, Kamila, leaving his only family in this world sealed away. Ever since the day he was revived, all he has thought about is bringing his sister back to life and, while he's at it, finding a way to kill Dark Diga and send him to hell. That would comfort his sister and let him apologize to her.

Tartarus: I know where Diga is. Are you in?

Trigger, you may not be Diga, but I can still beat you up a few times, right?

Sis, I kind of miss you.

The Ultraman who survived on prehistoric Earth all have, to one degree or another, a grudge against Diga. Come on, let's team up and go beat him up!