Hapori Dume is a Great Spirit, and the brother of Hapori Tohu. Both were split from the mighty being Hapori-Nui. Dume was the Yang to Tohu's Yin. Hapori Tohu was in charge of leading the Matoran of this world, to give them law and virtues, and give prosperity and morale. Hapori Dume was in charge of enforcing Tohu's law, punishing the criminals of this land, and weeding out the burdens of society. He enforced balance and order. For this reason, the Vahki were built in his image, and the Vahki sent to BZ-Metru were under his control.
Hapori Dume slowly went mad with jealousy over all the love and respect Tohu got, while Dume worked his butt off and got nothing but fear and hatred from the Matoran. He finally had it, and launched a massive strike against the island of Hapori-Nui. He tried to steal the comic land from Hapori Tohu. Dume had become far too powerful for Tohu to kill, but he had an ace up his sleeve. At the cost of the bulk of his power, Tohu was able to seal Dume away in a tomb underneath the land.
It appears he will return in The Third Movie.
Hapori Dume/Turaga DumeEdit
Hapori Dume has absolutely no connection to Turaga Dume of Metru-Nui, they merely share the same name and command over Vahki.
On the April 1st of 2004, BZPower was changed into Vahkipower by the invading Hapori Dume. BZPers were helpless, to fight him, but just as in the movie he was defeated by Hapori Tohu and banned from BZP.
Hapori Tohu and Hapori Dume are both supposedly characters created by the admins of BZPower. Hapori Dume's takeover was an April Fool's prank. They'll never admit it though.