Runuganga

, is a giant Hollow made of sand whose head resembles a sand castle.

Character Outline
He is the Guardian of the White Sands, and acts under orders to protect Las Noches from intruders. Being made of sand, he's immune to most physical and Kidō attacks, simply regenerating from almost any wound without fail. He can control the sand around him to attack, creating sinkholes and tornadoes. Though this makes him practically unstoppable in Hueco Mundo's desert terrain, it also makes him extremely weak against water and ice attacks, and he is easily dispatched by Rukia Kuchiki using her Shikai. In the anime, Runuganga is said to have many bodies since he basically just sand; killing his easily-dispatched, individual bodies does not kill him as a whole, so only an almost impossibly broad and powerful attack could ever hope to truly kill him.

Hueco Mundo Arc
Runuganga makes his debut in this arc, blocking the passage of Chad, Ichigo, Ishida, Nel, Dondochakka, and Pesche during their journey to Las Noches. The three friends from the human world attack the Guardian relentlessly, but their atytacks all fail, being similar in nature. They are eventually saved by the arrival of Abarai Renji and Kuchiki Rukia. Rukia uses her Shikai's second dance, Hakuren, and defeats Runuganga. However, as a last act of spite, he opens a sinkhole that sends the group tumbling into the Forest of Menos.