Ren Kunanzuki

The daughter of Rachnera's first host family. She tried - and failed - to adopt Rachnera back into her family out of guilt for her parents selling her.

Appearance
She looks like a normal girl. She's slim, her hairstyle is twintails and she wears a school uniform.

Personality
She has a bad habit of unintentionally insulting people without actively trying to. This is mostly due to her way of treating unexpected events. She thinks about any obstacle or strange thing as a challenge to overcome. When she's like that, she's nearly unstoppable and will go to the end of this challenge whatever the cost.

She is overcome with guilt about Rachnera being sold by her parents because of her. She tries to convince the other girls to let the Arachne to come back to her house in order to redeem herself.

Skills and Traits
Ren is perfectly human but seems to have a unusual willpower and sense of responsibility. Because of this, she's ready to do anything to achieve her goal.

Plot
In chapter 26, Ren tries to bring Rachnera back to her familiy (which was her previous host family). When Rachnera was living at her house, Ren surprised her and the arachne's claw accidentally hurt Ren. Because of that, Ren's parents sold Rachnera to some shady man.

When Ren comes to Kimihito's house, she takes everything as a challenge to bring Rachnera back and everyone can see her impressive motivation and the girls in the house don't know how to stop her.

Kimihito eventually simply refused to let her readopt Rachnera because she kept treating Rachnera like a challenge to overcome instead of an actual person.