Detective Haika

This is a perfect harem story plot. A boy named Shido Itsuka who supposed to be a normal highschool boy suddenly have to involved in some kind of organization which the boss is his sister, Kotori Itsuka. Kotori ordered her brother to calm the spirits who looks like normal humans to stop from making earthquakes on Earth. And so, the harem plot begin, where Shido have to make each of the spirits (which are girls) to fall in love with him.

Once the spirits fall in love with him and kissed him, they will lose their powers and lived as a regular girl. But there's also time where they are forced to be care and protect Shido, at that time, they could bring half of their powers back. In the end, Kotori Itsuka, Shido's sister, happens to be one of the spirits too, which Origami Tobichi accused as her parents murderer.
Did you know? For some reason each of the spirits have different personality. Kotori is Kuudere, Tohka is Tsundere, Yoshino is Dandere, and Kurumi is Yandere. Coincidence? Anyway, this anime season 1 didn't have the girl character with pink hair, it seems to only appears in visual novel and game. And they said, she will appear in 2nd season.

I came here to talk to you. I don't care what we talk about. As far as I'm concerned, I don't care if you ignore me. But... there's one thing I want you to know... that I-I won't reject you. (I won't let you make that face)
~Shido Itsuka