Dark Jak is an alternate identity of the character Jak from the "Jak & Daxter" series of video games. Dark Jak was introduced in the second "Jak & Daxter" game and has also appeared in the third game and in "Lost Frontiers."
Dark Jak is a result of two years of experiments conducted on Jak by Baron Praxis prior to the start of the second game. Jak gradually learns to control the power of his dark side, granting him powerful new abilities. The introduction of Dark Jak mirrors an abrupt tonal shift in the series, which had started out with more colorful, playful environments and had been aimed at a younger audience.