Board Thread:Questions and Answers/@comment-30737595-20170404140029/@comment-4867780-20170404210448

Omnipotence is nigh-impossible to reliably prove, and many writers introduce characters officially stated as Omnipotent, only to have them defeated one way or another alongside the storyline, with the underlying aesop that no one is truly invincible (whether for dramatic dynamic or inspirational ascension on the protagonist's part - defeating the seemingly invincible is a very popular trope). So you could simply do the same as they do, it seems to be working well-enough.