Ruber is a member of the Villain League and is one of its brutish members. He is also the main villain from Quest for Camelot.
Ruber was once a knight of King Arthur, trusted enough to be part of the order of the Round Table (though he wasn't liked much by the others, in many ways he paralleled the story of the Black Knight) - he desired the throne of Camelot for himself. He boldly tried to kill King Arthur in front of his fellow knights but the brave Sir Lionel defended the king. Enraged Ruber murdered Sir Lionel in cold-blood before making another attempt on Arthur's life. However, using Excalibur, Arthur beats Ruber back: Ruber, although strong is also a coward at heart and vowed revenge as he fled, yelling "One day that sword will be in my hand, and all will be mine!".
Ten years later he had his pet griffin steal Excalibur, although the theft was bungled and the sword was dropped into the Forbidden Forest. Ruber used a potion to transform his followers into an army of golems described as "iron men with hands of steel" and prepared to recover Excalibur and attack Camelot. However his plans were foiled by Lionel's daughter Kayley and her blind lover Garett. Ruber however did manage to gain entrance to Camelot and attempted to murder King Arthur yet again. However Kayley overheard Ruber taunting Arthur and boasting of his murder of Lionel - this prompted Kayley to slam a wooden beam into Ruber, launching him out of the window, she followed him and engaged in a battle with him, Garett attempted to strike Ruber from behind with his staff but Ruber blocked the attack and threw Garett into Kayley. Ruber proceeded to use his dark magic to graft Excalibur into himself (replacing his right hand) and prepared to kill the two heroes - however in his bloodlust Ruber is foolish enough to plunge Excalibur into the stone, since Ruber was not the rightful King of Camelot the stone's power activated and he is incinerated by the energies of Excalibur - ultimately being destroyed by the very power he had sought to obtain.
Role in the series
Ruber was originally the main villain from the Spongebob adventure of Camelot, but Scroopfan fell prey to his obsession of Spore, and had Ruber killed off when the Ogre sat on him, replacing him with his Mary Sue villain, Cobra, as the main antagonist. but, that doesn't mean he thinks ruber is not cool, and has some resect for him, as he is intended to return in future projects. he also had a romance thing going on with Cynder back when she was dark cynder, but scroopfan tried not to exploit it to much, cause it really didn't set well with the audience.