2. beauty
"Beauty is in the eye of the beholder."
For some reason, Nico got strangely offended whenever Percy called him beautiful. Percy, of course, found this very odd. In his eyes, Nico was possibly the most beautiful thing he'd ever seen. Starting from the top of his shaggy black hair, which was so long he had to tie it back, to the constant shield he had up in his dark eyes. Percy always strived to break through that shield, and gods was it amazing when he did. The way his eyes sparkled when he smirked, the way his lips would just barely turn up at the corners whenever he was trying to be angry but was honestly happy, and purely joyful sound of his laugh all made Percy's heart beat a little faster in his chest. His stomach flip-flopped whenever Nico got aggressively into kissing him after training. He loved the heated kisses, tinged with sweat and the lingering taste of black licorice that Nico always seemed to taste of.
But it wasn't just that. He also adored their more intimate moments. In his idle moments, he often found his thoughts wandering back to how Nico looked, curled up against him and barely fighting back the urge to sleep as they lazily sang along in front of the fire. He loved the way that Nico would blush heavily whenever Percy would mention their dates, but saw no shame in grabbing Percy by the belt loops and dragging him into a kiss if one demigod was eyeing him for too long. Everytime Percy complimented him, the little light that would spark behind his eyes was purely captivating, even if he vehemently shot down the praise seconds later. And, of course, Percy found it necessary to share these thoughts with Nico.
It was only once Nico woke screaming from a dreadful nightmare, one filled with horrible images of Percy dying, tortured, and crying out in pain, that he saw the true love buried deep within those sea-green eyes. After that, Nico never rebuffed any of Percy's comments on him being beautiful.