So I've been watching videos and scouring the wikis to get more of a sense of Warhammer 40k, but one thing I still don't understand is the Warp. I know it's not totally relevant to the RP, but I thought no harm in asking anyway. So far, I know is used to travel far distances between space, but what is a Warp Storm? Can the Warp just appear and spit out demons if there's a whole load of negative energy gathered in one place?