Kuro + Dora = Black dragon (katakana)
Kyne is the first prince of the Void Kingdom who was stripped of his title. He is the reincarnation of the black dragon. He has the strongest stats in the game, and has a younger twin brother named Abel. All his clear routes are bad ends, leading to Lulua either going missing or dying. To avoid these B routes, Lulua must always speak coldly to him and never cry in front of him, without exception.
https://nhentai.com/en/comic/onigashima-tanaka-onitaiji-otome-game-kuro-dra-kuroi-seijo-to-ashiki-ryuu-ni-isekai-tensei-shita-kedo-murige-tsunda
https://www.mangaupdates.com/series/hasbnym/otome-game-kuro-dora-kuroi-seijo-to-ashiki-ryuu-ni-isekai-tensei-shitakedo-murigeu-tsunda
Otome Game 'Kuro†Dora -Kuroi Seijo to Ashiki Ryuu-' ni Isekai Tensei Shitakedo Murigeu, Tsunda.