Genshin is a relatively new gacha game, meaning rerun banners are also quite unknown. It’s likely that Childe will come back about six months from now, but there are also other possiblities:
- He is added to the permanant banner (Wanderlust Invocation) although is is quite unlikely becasue the whole point of being a limited character is the exclusiveness. The permanant banner also has 15 five star characters and weapons on it already, and adding another would be troublesome to a large portion of the playerbase.
- He is permanantly retired and it is impossible to pull him ever again, also unlikely, because he’s quite a popular character. This would add a sense of FOMO to the game and encourage players to spend money for pulls, but would also alienate a large portion of the playerbase.
- He is added to a new banner containing previously limited characters, also unlikely, because there are four banners already (limited, weapon, novice, and permanant) and adding another would take resources and other logistics.
- Something else entirely.
I think Childe will come back sooner or later. If you don’t get him now, wait about six months, maybe a bit more, and in all likelyhood he’s probably coming back again.
Take this all with a grain of salt – I have no knowledge of what Mihoyo’s plans are or what timeframe they are operating on. Good luck with the gacha!