Oberon is the king and creator of the fairies alongside his wife and queen Titania, a race of magical beings, which come from Avalon, a dimension separate from earth. In Avalon there also exists a fairy Tribunal, which acts as a council of fairies that judge and condemn any being they find guilty. Oberon is described as a benevolent being by the fairies, although others state that is quite malicious when a certain incident affects the well being of his kingdom and people.
It is not known if Oberon leads this tribunal, and his actual power, abilities, origin and appearance have not been revealed nor known to the humans. But seeing that he is the lord of the fairies in Avalon, there is no doubt that he is the one whom ultimately decides the fate of the accused after the council reach a decision.
It is said that when Oberon is angry, his rage affects the very weather and causes nature to fall into discord. Considering that he is the king and creator of all fairies, as well as the designer of many powerful magical items known to the kingdom of the fairies, Oberon is quite possibly an unimaginably powerful being.