Gluskap, the heroic figure, was good. He was a giant, although he appeared to the Wabanaki as one of them, in human form.
His twin brother was not good. Some versions of the story of the twins suggest that the brother, often called Malsum, the wolf, was born out of his mother's side, killing her.
Malsum, who also had great power, did not want Gluskap in his way, and attempted to kill him. Gluskap outsmarts his brother and the "bad" brother dies.