i remember that the knight saw 2 blue, 1 pale blue and 1 green demon in the palace. it the stands to reason that Tom is the pale blue, Rammus and Exador blue and Rupert green.
Tom is a new demon so he still have a lot of time to get better at magic and it looks like he found some way to make himself stronger from that god at the end so he is probably stronger now or got some other special power from that. Maybe he can do it again on their gods/demon/wizard or the same god again but i don’t believe that will happen any time soon.