The idea is everyone gets their spirits trapped in swords. One Kirb goes around to save the world, and collects the swords with spirits. Each sword lets the player use the spirit's powers, but for a limited time. Your OC can be Sword, Boss, or NPC. It could also be a few types, like a boss that drops a sword when defeated, or an NPC that gives you their sword when you do their quest.
Art and various game concepts created by @ItsOli23TEST