Random Chiyato/Ayatochi headcanon that's been very active in my head that I finally decided to spit out in somewhat a fanfiction form because I read way too much AO3 stuff about them yesterday
Ever since Childe left the abyss, his eyes didn't shine, and when they did, it was barely even a fraction of what they used to be
Until he met Ayato. He knew a bit about Ayato, what he was like, his daily life, how he looked, but he hadn't expected how much prettier, graceful, attractive, so much more-
He had to stop himself there before he was too distracted, but he found him tracking every movement Ayato made, his eyes tracing every part of him. Ayato noticed, but he didn't bring it up.
At first, no one seemed to notice, until it became quite obvious how much more... Cheerful- not quite the right word, but it would have to do- Childe seemed around the young commissioner. Ayato had taken note of how his eyes only shined when he was around him, the small white dots disappearing once the harbinger interacted with someone else. He found this quite interesting and absolutely adorable. Who knew those eyes could still shine after everything he had been through? He often found himself staring at the little glistening spots in his pretty blue eyes when they interacted, knowing he was the only person who could make those appear.
Childe didn't know until a somewhat concerned Thoma brought it up, leaving a slightly flustered and embarrassed harbinger and a mildly disappointed Waka. He had hoped that Childe would notice himself, but someone would've probably told him eventually anyways. At least he was there to see his face when he found out.