Kid Buu was the “original” Buu, before he absorbed the Kais and became Fat buu. Kid Buu was pure evil, as Vegetto pulled out the Z fighters from Super buu, Super buu reformed into Kid buu. Kid buu may be small, but he's the last villain in DBZ, and immensely strong. Kid buu can split up into millions of different pieces and reform again. Kid buu had even destroyed the Earth back when he was Super Buu too, (the Earth got wished back). Kid buu was the creature that Bibidi had originally summoned and was the most powerful villain of DBZ (if you don't count Super Buu). Goku had to create a giant spirit bomb with the energy of the entire universe in order to destroy him. Goku, Gohan, and a few others were the only ones who survived when Super Buu destroyed the Earth, (Goku had to use teleport).
Attacks: seeking blast, tron attack, super ki blast, renzoku energy dan, power ball, kiko-ha.
Power level at beginning of DBZ: N/A
Power level at end of DBZ: 500,000,000
Class: Buu