>>2301899It was implied that the blue one (Saphir) had a thing for Demande.
In the manga, he tried to kill Sailor Moon because he felt that she was responsible for all the trouble they were going through, and making his brother become obsessed with him.
In the old anime, he told Esmeraude that they had a lot more in common than they thought after they shared their hatred for sailor moon. (Esmeraude hates her because Demande is in love with SM) He even said something along the lines of "you really don't think I understand your feelings, too?"
TL;DR Ikuraha worked on this series, and he loves putting homos, and incest into his works so i'm not surprised with the pairing.
