(This HeadCanon was suggested by @Kateryn_Howard )
Togami, Sonia, Rantaro, Celeste, and Nagito are called the Rich Kid Squad because they're all rich and Togami literally made this group just so he'd have some friends that were up to his standards. Togami trusts this little friend group with his life and everyone in this friend group feels honored that they are the few people who get to see the soft side of the Heir. Also, Amami gets all flustered when people playfully tease him about being part of the Rich Kid Squad and because of this Rantaro has ended up being the baby of the friend group.
