Hindu religion also accepts that there is only one God, who is invisible,omnipresent,equally available everywhere.But unlike Islam religion ,the supreme Power ,the God has deputed it's representatives-Like-Lord Shankar(Killer God),Vishnu(God who brings up),Brahma(God who gives Birth),Gods of air ,water ,fire,Goddess Durga ,Kali,Hanuman etc to look after different works.These representatives are nothing but exalted souls from ourselves who may be keep on changing after thousands and thousands of years,depending upon tenacity of we people who live on the earth.Again the above posts/portfolios are granted to the people of more tenacity.It is just like Parliamentary system of Prime minister with MP of different Portfolios,where the Prime minister/the God can not be replaced/changed but the MPs are replaceable depending upon their deeds.