Is this incest? The cover contains the yellow hair is the yellow hair is his cousin?

The blonde prince is indeed her cousin but they only share familial affection (like brother and sister). The male lead is his best friend, the dark haired duke

Yeah, he appears in the cover because their relationship is really important, but they never share more then brother/sister love, so nope, no incest hehe

lolllll i just made a comment asking about their relationship because i thought the blonde one was going to fall in love w her then i remembered that they’re related.