When Rowan Oakwood discovered Apex Hunters were targeting Sasquatch near waterways, they sought ancient protection techniques from Japan. A Guardian who had studied with Kappa protectors returned with specialized knowledge, becoming the first Kappa Custodian. They adapted these aquatic defense methods to Pacific Northwest rivers, creating a new line of protection against water-based intrusions.

The Kappa Custodian possesses enhanced aquatic abilities including water breathing and rapid swimming. Their hands bear faint webbing between fingers for powerful strokes, and their skin secretes a protective mucus layer when submerged. Most remarkably, they can create whirlpools and manipulate water flow to misdirect intruders, though they must maintain the water-filled depression atop their head to retain these powers.

The Kappa Custodian patrols forest waterways to prevent Apex Hunter incursions, using aquatic misdirection techniques to protect Sasquatch drinking sites and river crossings. They serve as both protector and educator, teaching younger Guardians ancient water spirit lore and defense strategies.