human to beast in the apocalypse

the mana finally reached earth as every living thing begin evolving animal and pet became beast killing everything in there sight plants became beasts that grow teeth that can bite through the toughest iron and there body became tough as metal human evolved and get stronger and when they reach level 15 they could mutate there gene into beast given to them the beast that will appear have something similar that happen in there live but if your body couldn't handle mana you will turn in to mindless beast eating flesh . . let's follow the journey of Jordan and Jake a twin in the apocalypse