Касеґі

A human and a con artist who claims to be associated with the exchange project and bullies his way into Kimihito's house on the pretext of making a documentary, while using the alias "Kasegi". Using his ability to manipulate people, he attempts to create an exploitation film about the girls in order to steal Papi's egg and Miia's cast-off skin,[ch. 14] but is ultimately foiled by Suu and Kimihito. It is later revealed that he has kept Rachnee in his house under near-prison conditions for financial gain by selling her silk. After Rachnee has enough of him, she wraps him up with her web and leaves him to be arrested by the police; his current fate and whereabouts are unknown.

In Chapter 55, it is revealed that he is the older but worthless brother of The President of the as-yet-unnamed corporation and that before she kidnapped Kimihito, Rachnera tried to bargain with The President: her safety in return for keeping the brothers' relationship secret. (Source: Wikipedia)