You are not the most powerful. As mentioned before, you have statistics (high ones, but stats nonetheless) - Us Old Ones do not even HAVE hit points because you need to wipe out all that exists in every dimension, plane and phone box (including yourself) to destroy one
And if somebody WAS going to do that we'dknow in advance (premonition) and travel back in time to wipe them out when they're born
However I am not a villain here, so I'll just put out your hellfires by relieving myself
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In the kingdom of the blind, the one-eyed man is pimp.
Lord Raptor's Site