In Norse mythology, which god rules over Valhalla?

Valhalla, in Norse mythology, is the hall of slain warriors, who live there blissfully under the leadership of the god Odin. Valhalla is depicted as a splendid palace, roofed with shields, where the warriors feast on the flesh of a boar slaughtered daily and made whole again each evening. They drink liquor that flows from the udders of a goat, and their sport is to fight one another every day.

The slain warriors will live until the Ragnarök (Doomsday), when they will march out of the 540 doors of the palace to fight at the side of Odin against the giants. When heroes fall in battle it is said that Odin needs them to strengthen his forces for the Ragnarök.

Odin is a widely revered god in Norse mythology. Generally depicted as king of the Norse gods, Norse mythology, the source of most surviving information about him, associates Odin with wisdom, healing, death, royalty, the gallows, knowledge, war, battle, victory, sorcery, poetry, frenzy, and the runic alphabet, and depicts him as the husband of the goddess Frigg.

Ragnarök is a series of events, including a great battle, foretold to lead to the death of a number of great figures (including the gods Odin, Thor, Týr, Freyr, Heimdallr, and Loki), natural disasters and the submersion of the world in water. After these events, the world will resurface anew and fertile, the surviving and returning gods will meet and the world will be repopulated by two human survivors.