Daniel was you're average person, 19 years old and not long to finishing college. On his last day everything he knew went wrong when he met a strange Unicorn. After his encounter he died but he was reborn later and merged with something nicknamed 'The Heart'. While this gives him quite a range of powers, he also finds out his mental state is unchanged and he can't fully control them.
With his lack of training with his powers it makes him determined to train and learn to control them so he can avoid hurting himself, and others. As he does this he also does all he can do to keeps himself from using his powers a lot in public, fearing it will hurt his sister Annabelle or it will lead to them them being discovered.
Not long after a event that leaves them without their parents, they enter Equestria and just wish to live peacefully without any of the ponies knowing what they are and what Daniel is capable of, but I seems that fate has other plans for him.
Note: I don't have the best Grammar so if you want to read this just be prepared for Grammar Errors every now and then.