Tonko House on Instagram: "INTRODUCING...KAPPA! Kappa is Onari's BEST FRIEND and the most loyal sidekick a hero could ask for. Kappa is cautious, polite and a bit timid, but has a heart
Encyclopedia Mythologica - Kappa
Japanese Kappa Monster: A Fascinating Creature from Japanese Folklore - Old World Gods
Oni: Thunder God's Tale by KABANOMORI on DeviantArt