Dear Jacob, there is exactly one God and he may assume any form for the welfare of us, His children. Bible and Quran say that God sends prophets on earth to spread the message of devotion to Him. In Bhagvadgita, Lord Krishna tells that for the sake of eliminating unethical elements, God Himself takes the form of human or other living being. Now this 'incarnation' of God has extraordinary powers. Prophets too have them but they may not like show them always. It was for teaching us humbleness that Ram (himself incarnation of Vishnu) worshipped Shiva; not for seeking any boon but for the sake that people stop comparing God's one form (Shiva) with other form (Vishnu).
