Altered plane: I am a boss class monster

How far are you willing to go for family? In the universe, powerful beings beyond anyone's comprehension live in the depths of the unknown. These beings consist of the Grand Order a powerful entity that little is known about and Calamity gods, those that warp time and space in order to fulfill the Grand Order's will. Each century, a Calamity god is selected from the planet of an intelligent race in order to ensure the continuity of their race as Calamity gods are not immortal. This selection process is a long and difficult one, with the strongest of that race becoming a god. Cree, an orphan boy who had been adopted by his close friends family is put to the test when he comes across the worse news of his life. His foster parents and sisters die in a car accident leaving him with his close friend, Callum. Unable to live with this, Callum ultimately tries to commit suicide. While trying to convince his friend not to do something so stupid, things end in the worst way possible as the world changes unexpectedly and drastically. While grieving the loss of his close friend, he comes across a Calamity class being, Claire, who has taken some interest in him. She proceeds to tell him that it may be possible to bring back his friend if he was to become a Calamity god, however in order to so, he would have to be the most powerful being on Earth by conquering 'Rift cubes' that appear in this new terrain. Cree goes along with this plan unaware that the power he gains may cause him to lose his humanity. Little does he know it may cause him to be a terror that roams this new apocalyptic world. "I will do anything it takes to bring him back!"