Jean Grey aka Phoenix

Let's start with the one we all know, Jean Grey. She is an empath and has telekinetic abilities at the same time, plus she is favoured by the Phoenix Force. What movies failed to explain is the origin and details about the Phoenix Force itself. Phoenix Force is a cosmic entity which embodies a life that is yet to come into existence, which basically means it is some sort of god.

Usually, a powerful empath like Jean Grey is entitled to be the incarnate of this primal cosmic energy. Since it is an entity that operates on such a high level of power, it is hard to reason with it on a human level, which makes it a dreadful opponent. When Jean is possessed by the phoenix, all of her existing powers receive a gigantic boost, plus she can manipulate molecules in order to create heat.