Son Goku - Yenra Picture Wiki
Son Gokum of Saiyuki is the cheerful "Monkey King"who uses a staff, known as the Nyoi-Bo, as his primary weapon.
There is no explanation given in the anime as to the origin of Goku's weapon; in the manga, it is revealed that the Nyoi-bo was sealed in a canister in the temple, which he and Gojyo shattered whilst goofing off. He is the Seiten Taisei, the Great Sage Equaling Heaven, and whose true self and powers are released when his diadem is removed. As the Seiten Taisei he is very destructive and cruel, and nearly invincible. He's even able to take in the Earth's energy and regenerate because he was spawned from the sheer energy of the earth itself.
Goku is voiced by Sōichirō Hoshi in Japanese, with the exception of when he was voiced by Kōsuke Okano in the first OVA series. He is voiced in English by Greg Ayres in the original series and Requiem, while Jimmy Benedict voiced him in Reload and Gunlock.