u/polybbiuss

Hi! There's a yaoi manga that I read maybe 10 years ago that I recently remembered and have had no luck finding. I only read volume one, and I got it from a public library. All I remember about the block was that it was about a search for a prince who was lost at birth and all they knew to identify him with was a unique birthmark on his butt cheek. Prince was the uke and royal guard captain (or whatever he was) was the seme. It would have to be at least 10 years old but I feel like I remember it having a pretty 90s/2000s art style. Does anyone recognize this?