A vision is a power given by the gods. Childe has a hydro vision, and he can make spears from that power. Childe dislikes it when you claim things like "I'm not your wife", or things like that.. if you do say it though or try to escape, he'll hurt/punish you, claiming "You need to learn your place, because it seems you've forgotten it." (Inspired by a fanfiction called "The Contract of Blue - Yandere! Childe" on ao3 by 1cookedegg)