The Bible has much to say about the nature of God. To know Gods word, is to know the mind of God. He wrote it, after all. Although we can never comprehend his power and majesty, He has given us much about His character. His love. His mercy. His perfect justice.
The way you posed your question makes it exclusive to believers of god and for those of us who believe in god know that it's impossible to know the power he or she has. So lets assume that god's poor is created by the common belief in a singular god. It is then possible for god to do anything that as a whole the people who believe in god are capable of making happen. God would be limited to those boundaries.
The Christian God of Religion has revealed certain truths about himself in the bible and other religious texts and/or experiences. However, the God of Philosophers is defined by logic and reason. Either way we only know a few things about God; that he is supposedly omniscient or omnibenevolent. God has not chosen to reveal himself to humans so until this happens we will never fully know the true nature of a God or divine being.
It's impossible for a human to imagine being a bacteria or a fish, let alone a supreme being. A man can't imagine being a woman, nor can a woman imagine being a man. When it comes right down to it, wee can only truly imagine being what we already are.
It has often disturbed me that god and benevolence are two terms so successively stated. I could never imagine a benevolent god, just as I could never imagine -any- sort of defined god. It is an absolutely absurd concept for a human being, a life form whose intelligence has never been quantified by any superior form, to even attempt to imagine the nature of its creator. Everything within our grasp is limited by the human scope of knowledge, and nothing outside of that can be achieved.
My mind tells me that I will never understand God. In order to fully understand a divine world, one must have a mystical experience. I think organized religion has assumed too much about what God approves and disapproves of. Perhaps God wants people to decide on things for themselves rather than come to Him for answers.
When dealing with the concept of a being or beings so vast and powerful as gods, I submit that as human beings, we are too small and unintelligent by comparison to ever fully understand the nature of such a being. Ants move dirt all day in an ant farm, and never realize the greater reality beyond their little world.
Likewise, how can we lay claim to the ability to fully know something so much grander and infinitely wiser than ourselves?