People who are new to Daine would think he is a schizo. However, he is not. Daine is the human side, while Leonardo is an alternate side, made from an angel who fused to Daine.
As Daine: Daine is a fun-loving, food-loving, awesome friend. He's kind to everyone. Daine can be a jokester sometimes, but not all the time. There are moments where he gets serious, but only when the situation commands it.
As Leonardo: Leo is always serious, and he will usually take command. However, Leonardo has softened outside of battle over the years of being with Daine, and would sometimes play a prank by acting as Daine.
Human:
Devil's Eye Blade: A gunblade that used to belong to a demon, but is no wielded by the human side Daine. When pointed at an opponent, the opponent would feel like the Devil himself is searching for him/her.
Twin Pistols: Self-explanitory.
Guardian Angel:
Michael's hand: A sword that glows with holy light. Leonardo obtained this after becoming a Guardian Angel.
Angel of Death:
Darkened Dawn: A black scythe that Leonardo obtained when becoming an Angel of Death, an Angel in charge of carrying souls to heaven for their Judgement.
Human POV:
Daine, ever since he could remember, had been begging on the streets. When struck with a disease, Daine had only a few days before death. After all, living on the streets had made his mortal body so weak. However, his life changed when an angel, Leonardo, offered to fuse with Daine. Daine quickly agreed, and now has a physically enhanced body. With this body, Daine was able to survive and stop living on the streets. He got himself a job and made money for a year or so, but then started to become a vagrant.
Angel POV:
Leonardo was an Angel of Death. His task was to carry souls back to heaven, and protect them from being dragged down to hell by demons. However, Leonardo was one day charged with the task of becoming a Guardian Angel to one of the humans. Leonardo took the task. After a while, Leo began to grow fond with the human, but she died in a car accident. Ashamed because of his failure, Daine stayed on Earth. There, he saw a young boy, about to die. The boy didn't even live a normal life, so Leonardo took pity and offered to help him. The boy agreed, and they fused. Now he goes wherever the boy goes, helping him and sometimes playing jokes on him.