Isekai Maou to Shoukan Shoujo no Dorei Majutsu

Synopsis

Celestine directs the group to the slave trader, Medios, who was once Celestine's colleague in studying magic, for insight on how to remove Rem and Shera's collars. When they meet Medios, she detects Krebskulm's presence within Rem, but Shera thinks she is saying Rem is pregnant. Medios explains a master can remove a collar by pouring their magical energy into their slave's body. Diablo tries it with Shera, but gives up in embarrassment when the process is extremely pleasurable for her. Later, Shera's brother, Keera, arrives and apologizes for the bounty hunters, then tries to persuade Shera to return with him. She reiterates that she will not return, so he leaves, promising that she will return with him of her own free will.

(Source: Wikipedia)