Broly has an unpredictable dual nature. This violent and maniacal side of him seemingly stemmed from both his extraordinary power that he never properly learned to control as well as the traumatic events of his birth. In an effort to control his erratic behavior, Paragus (Broly's father) used a device to subdue Broly's temperament. Broly now rarely speaks and constantly looks sad. He is unable to get angry... Unless he experiences a lot of emotion, or sees one of his triggers.

This is Broly wearing Paragus' mind control device

A hedgehog from 200 years into the future that has come to change the past and make his home a better place. He has psychokinesis. He is a kind-hearted and well-meaning individual driven by a strong sense of justice to right the wrongs of the past to uphold peace, though he is somewhat naive and immature. Despite the monumental tasks he may have on hand, he is an optimist and will do whatever is required to protect the world. He believes in standing up for those who cannot stand up for themselve

A hedgehog from the future

He is a very closed, confused and kind-hearted person. He used to be friends with a giant green furred monster that he called "Ba" because of the sound it made. Broly has a more sane and honourable personality than most saiyans. He also has a very formal speech pattern at times.  He is a pretty peaceful man who doesn't desire to fight except for those he cares about. Broly is, by nature, very kind-hearted, sentimental, and quite friendly once his trust is earned.