Moori is one of the Elders of Namek.
When Frieza and his men came looking for the Dragon Balls, Moori refused to turn over his ball. He finally conceded when they threatened to harm the children. During their battle, Moori discovered that their scouters were what helped them located the other Namekians and the other Dragon Balls. He destroyed them all before he was killed, slowing them down from their quest.
Moori returned to life with the Earth Dragon Balls and was wished to Earth along with the other Namekians to survive the destruction of Namek at Frieza's hands. Before Grand Elder Guru passed on, he named Moori as his successor.