Storm King and Skar King: Both their first names start with "s" and ends with "King", both are simians who command a legion of other apes, they're conquerors, and their primary weapon has a crystal inside it.

Tempest Shadow and Shimo: Both are the female second-in-commands and secondary villains, they are more powerful than their commanders, and they're actually being used. Also, they can freeze others (Tempest has the Obsidian Grenades and Shimo has her ice breath).