Anyone know the name??

So since everything ive been building up in 5 years got whipes away Im looking for this one BL manhwa where its based in a power system society where the ml has a third leg ( a big ) and its huge and shiny he uses as a super power and the mc can neutralize that and make him normal and he instantly becomes obsessed so they fall in love

ML has blond hair and blue eyes mc had black hair and red eyes I believe please help!!