Dexter goes a bit overboard when he gets the opportunity to avenge his mother’s murder and his own origin. He tracks Santos Jimenez to his cabin in the Everglades. His usual method of knifing his victims just isn’t good enough, so in this case, Dexter adopts an eye-for-an-eye approach and kills his mother’s killer with a chainsaw.
Dexter’s pride got the best of him when he faced off against the Trinity Killer. After months of palling around with and learning from the twisted murderer, Dexter finally got him on his table. However, the long road to claw hammering Arthur Mitchell proved too windy, and Dexter accidentally revealed his true identity, costing Rita her life, and their young son his innocence.
Dexter’s saddest kill was that of the Ice Truck Killer, a.k.a. Dexter’s long-lost older brother, Brian.
Brian toyed with Dexter throughout the season by leaving his victim’s remains in locations around Miami that had emotional significance to Dexter, thus unlocking his blocked memory of their mother’s tragic death. But Brian took it too far when he romanced Dexter’s adopted sister, Deb, and then attempted to eliminate her from Dexter’s life. In the end, all that Brian wanted was a brother, but he was too traumatized and hollowed by his mother’s murder to know how to play well with others.