Ruyi Jingu (a.k.a. Yeoui) is a sacred weapon that is used by the Monkey King of the Nine Kings. The Staff, together with Kinto-Un and Gourd, forms Weapon of the Three Gods, The Monkey King's Weapons of Choice.
After RagnarÖk, Ruyi Jingu has been broken into two pieces, with one of them embedded at the center of the main battleground, Korea, now obliterated and become a sea. The other piece falls in possession of Jung Mo-Ri.
The Ruyi Jingu takes the appearance of a silver bo staff. In the First Heavenly War, Ruyi Jingu had a gold band on each end.
Ruyi Jingu was a stone column that was held in the Dragon King's Palace that no-one was able to move. The Monkey King extorted it from him.
Ruyi Jingu is able to grow on command to what the owner says and is capable of killing thousands of gods instantly. A casual strike with Ruyi Jingu destroyed many Gods at once, ripped Taek in half, and made a huge tsunami. The staff is also deceptively monstrously heavy, with few people besides the Monkey King being able to even lift the staff.
Size Alteration: Ruyi Jingu's size can be altered according to the Monkey King's will. It can grow broader or slimmer and taller or shorter at will. It can reach incredible lengths, as it was able to reach all the way from the moon to the earth which is 384,403 km (238,900 miles) long.
Weight Alteration: On command the staff can become lighter or heavier and the norm for the Monkey King is heavy by many people standards, just placing it onto the floor was able to create cracks in the ground that reverberated up a gigantic hole up to its surface. Making it lighter vastly increases movement speed.
Levitation: Ruyi Jingu can levitate itself a certain distance from the ground.
Summoning: The staff can be summoned into its wielder by moving at incredible speed, destroying anything in its path.
Cloning: Ruyi Jingu can make multiple copies of itself along with with The Monkey King's own copy. The clone's staff is vastly weaker, however, as it is easily cut through and broken by Blade of Tathagata, while the original was durable enough to withstand its cutting power. When the copy of Ruyi Jingu held by Hui Mo-Ri is broken to pieces, it can regenerate. This regeneration ability doesn't extend to the original Ruyi Jingu.
Enhanced Durability: The staff is incredibly durable, with few if any attacks able to break the staff. So far only First Crown Prince using Lightning Blade managed to cut it, something that The King, using his Blade of Tathagata, failed to do.
Teleportation: Ruyi Jingu can be teleported back to The Monkey King's location at his command
- In the Journey to the West, Sun Wukong won this staff in a challenge held by the Dragon King, in which it stated that if he could lift it he could keep it.