Patalliro!

Patalliro du Malyner VIII is the crown prince of Malynera, a nation known for its diamond wealth. Despite his unattractive looks, mischievous nature, and unpleasant personality, he’s fiercely determined and a loyal son to his father, the king. Many of the kingdom’s enemies, including Malynera’s own prime minister, want to remove him and seize control of the prosperous country. To protect him, Bancoran-a proud but strikingly handsome bodyguard-is tasked with keeping the troublesome prince safe, even from threats like Bancoran’s own lover, the stunningly beautiful bishounen Maraich, and other bishounen assassins.