JK Shiiku ~Junpaku no Shojo ni Midara na Kioku o Ataeru Otoko~

After losing your beloved pet, you’ve been feeling down. On your way home, you stumble across a high school girl with amnesia.
You can’t just leave her there, so being the kind-hearted person you are, you take her back to your apartment.
That night, unsure of who she is or where to go, she offers the only thing she has—her body—as thanks for taking her in.
To comfort the anxious girl and satisfy your own (healthy) desires, you decide to take her virginity.
You give her a name, and the two of you begin a sort of weird cohabiting.

With nowhere else to go, the innocent high school girl has no choice but to stay in your apartment.
You can’t let this opportunity go to waste!
As you mold her into your ideal companion, you also search for clues about her past.
Depending on what you find, you might uncover her surprising true identity…

[Translated from dlsite]