The two have never met nor interacted due to the fact, the two live in different nations. Kaeya lives in Mondstadt, though formerly in Khaenri'ah. While, Childe lives in Snezhnaya. They both don't have voicelines of each other, and can be rare to have voicelines of each other due to being from different nations.
Gameplay-wise, these two could notably work, as an significant duo since the two could do the elemental reaction, frozen. With their skills and bursts.
However, the two have some similarities, they're both, tall within their appearances, but they're also said to have the same height, though it isn't yet confirmed. They have visions or are a playable character, they have a brother. But for Kaeya's, it can be both be, a slash or family. The two also has something to do within the Abyss, shown in Childe's Voiceline about Interesting Things, he was able to ventured the abyss and trained there. And for Kaeya, he was formerly in Khaenri'ah. Whom originated from the destruction of Khaenri'ah.
- “ I once ventured deep into the abyss and came face to face with an enormous beast. I don't know its name, all I know is the sight of it chilled me to the bone. But mark my words, one day I will march back in there and behead that beast, and you, comrade, will be my witness!”
- — Childe's Voiceline about Interesting Things
- “Is the Abyss Order causing you trouble? If there's anything bothering you, you know you can talk to me.”
- — Kaeya's Voiceline about Kaeya
Cheaya is a popular ship within the Genshin Impact fandom, considering how many supporters are there, its rivals ships are ChiLi, ChiLumi, and KaeLuc. It's one of the most written fanfictions for the two of them, being the 4th most written fanfics for the two of them. Currently having 611 works on AO3.
The two are usually portraited as an "Enemies to Lovers", since Childe is one of the Fatui Harbingers and Kaeya supposedly a Knights of Favonius and protects Mondstadt but was an agent from Khaenri'ah. Their fanon interactions are always angst, considering how there are many angsty fan arts and fanfictions there are.
- Chaebedo refers to the ship between the two and Albedo
- DCKZ refers to the ship between the two, Zhongli and Diluc Ragnvindr
- ZhongChaeya refers to the ship between the two and Zhongli