Basically cheerful and lively with common sense, but short-tempered and crude. His cunning and ruthlessness toward others are that of a bratty kid. Incidentally, he has been selfish, prone to getting carried away, and twisted since early childhood. On the other hand, he is a hardworking and compassionate person with a strong sense of justice. He is highly sensitive and honest to a fault; despite his delinquent act and harsh way of speaking, he tends to look after others. Furthermore, he does not look kindly upon taking lives and rarely tries to kill even his enemies. To put it kindly, he is deeply compassionate; to put it harshly, he can be naive. He shows intense rage and sometimes resorts to retaliation against those who try to (or do) harm his loved ones. As a State Alchemist, he sometimes adopts a mature attitude, but he is still mentally young and immature. He has great initiative and acts immediately once he sets his mind on something, but he tends to move on to the next step (or fail and cause problems) without consulting those around him. This is one reason why he is easily deceived by cunning beings like the Homunculi, and his usual delinquent behavior leads those around him to perceive him as a troublemaker.