He’d probably mistake his feelings for a desire to eat them, and start his game by inviting them to coffee. Meanwhile, he’d insist Chie follow them to discover what activities they like.
Shuu would then show up to coffee bearing flowers, their favorite book, or something related to their hobbies – whatever Chie found.
After a while, he might realize he enjoys meeting them because he likes their company, and he’d miss them if he ate them. This confuses him, so the person might actually have to be blunt about how
a) they know his intentions
and
b) “you’re actually experiencing a crush, silly.”
They may also say they totally talked to Chie and figured out Tsukiyama’s identity.
They will then have to talk Tsukiyama out of the immediate marriage he suddenly wants.
He will spoil them rotten, refer to them as royalty and have several dozen pet names for them, and tell Mirumo about how much he likes them. And Mirumo will then like them, because he’d be glad his son stopped confusing crushes and food.
Mercy and Magic 