Before Ninjago, there was Knights' Kingdom II (which had nothing to do with Knights' Kingdom.) The similarities include outrageously colourful costumes and crappy storylines. They also had BIONICLE versions of their characters that no one bought.
In the first wave, King Mathias' adviser Vladek captured him and hosted a contest to decide the new king of Morcia. (That's how monarchy works, right?) The four main knights had later rescued the king, who told them to go find a secret magical heart of some shield to win the contest. In it, they had to face many challenges, including the last, being respectful to your elders. One of the knights, Jayko, then won the contest and had Vladek locked up rather than killed so that it's kid-friendly. (Oh, and Mathias got to keep being king anyways.)
In the second wave, Vladek had escaped and started a new kingdom called Ankoria. His ego had caused him to make a statue head of himself that would destory Morcia. The knights got cooler, newer armour and then set off to defeat him. Long story-short, Jayko blew up the Vladmask, "killed" Vladek, and became king.
In the third wave, they decided to only keep Jayko and scrap the other knights. They also aged him 50+ years and gave him two new sidekicks. Jayko, for some reason, wanted to reforge that magical shield mentioned in the first wave. Oh, and Vladek had also been somehow still alive. In the end, Jayko got the shield reforged and trapped Vladek in a crystal orb.