how about mukuta's essence some how survives the final battle against mata nui(by the power of plot convenience) and ends up in a new solar system and finds a planet inhabited by robots, so mukuta hatch's a plan take over the planet, so he makes some rahkshi and sends them to attack the inhabitants. after a couple attacks mukuta makes a new body and claims to be able to help the people and he creates a city. he also calls himself mr.mackuhero (not sure if I spelled that right) and makes the "heroes" to ward off "evil". unknown to both the people and the heroes that the heroes' core is not actually quaza crystal but is actually energized ANTIdermis and that they were made to be used as an army against mata nui. the villians of the series are either actually bad, labelled out laws because they found out about mukuta, or they are simulations to test the heroes' strength.
pretty crap huh
another one is good guy being a great being above the great beings.
after mata nui goes back into the mask of life, the toa ignika comes back.
ahkmou finds a krekann and becomes a toa of shadow.
kopeke, macku, onepu, hafu, kapura, and sanso (or Defilak) get forced into becoming corrupted toa working for ahkmou.
the vahki come back.
turns out ernakk was real and thok is his re-eincarnation with vesok and avaks destiny was just to become a part of him.
mukuta makes bohrok and visorak of shadow.
in response the bahrag make bohrok of light which turn bohrok of shadow into regular bohrok.
a toa of evil lime green is made
a toa of rocks is made
zactan gets a 6 bladed scissor
the piraka sing the piraka rap
nektann gets a piraka code name of the "breaker"
bad guy becomes a piraka and gets called the "meanie"
ALREADY IS AN ANIMOO
Edited for Double Post.