Season 4

Daolon Wong's failed attempt to escape from prison through the use of magic reawakens Tarakudo, the king of the shadowkahn who is bent on recovering all nine oni masks that imprison his generals. Tarakudo attempts to free himself and his minions so that they can unleash total darkness upon the earth.

Ratso obtains the next Oni mask and has summoned a new deadlier type of Shadowkahn with sharp metallic claws and razor pointed feet that appear to be unstoppable. Meanwhile, Uncle begins to doubt himself as believes he is no longer useful to the group because he is not well versed in Japanese legend and magic.

A new Oni mask has been discovered in San Fransisco. Will Hak Fu finally get to wear the mask? No! Who better than Jade's dog scruffy to command the new tribe of winged shadowkan?

While attempting to stop the Enforcers from getting the fourth oni mask, it accidentally lands on Captain Black's face. He uses the powers of the mask to help him easily take down the Enforcers. Jackie and the rest of the group become worried when Captain Black becomes very intrigued and excited by his newfound abilities. Captain Black's true good side is able to ward off the influence of the mask for a while, but the dark power of the oni begins to slowly corrupt and take hold of him. When the darker oni Captain Black finally emerges, he attempts to take advantage of his full access to Section 13. Jackie, Jade, Uncle, and Tohru race to work on a way to keep the other three stored masks away from Black as they search for the ingredient needed to perform a removal spell.

Jackie and the gang gets the next Oni mask and also found the archive of the demons. The mask that they found happends to have a full chapter on the mask so Jade asks lets put the talisman on the mask and question it? Somehow the mask jumps on Tohru's behind and on to another and another until it finally reaches Finn's car. Tarakudo asks everyone to find it because it has found its way out. So finn takes a walk to his car and sits on the mask. Long story short, they capture Tohru and the mask forces him to put it on his face so then Jackie saves the day once again.

Paco tries on a mystical Oni mask in order to outdo Jade's scary costume on Halloween.

Jackie and the enforcers locate the seventh oni mask at a yard sale where it is eventually bought by a man who owns a site the sales antiques. It is then sold and won by some rich guy who ends up being Valmont. Jackie and the enforcers go to Valmont's apartment to get the mask and there is a big fight. During the fight, the mask is broken in half by Hak-Foo and one half goes to Valmont and the other is caught by jade. Valmont puts on his half and summons half of the shadowkahn. Jade puts on the other half and summons the other half, which don't have heads). They end up in a building where the two halves of the maske get together and combine the shadowkahn into one so that they can defeat Jackie. While this is happening, Jade and Valmont are trying to get the half masks off themelves because Valmont wants money and the mask wants power. Eventually they get the mask removal potion and take the halves off each other.

After many failed attempts to acquire the power of an oni mask, Hak-Foo finally gets one. He is a disappointed in the small size of his shark like shadowkahn, but Hak-Foo soon discovers their monstrous appetite for devouring shadows.

Ratso, Finn and Chow decide to become good guys, but they realize they're not much better at being good than bad!

Jade gets the surprise of her life when she is visited by... herself, from the future! Future Jade is trying to stop Shendu's son, Drago, from getting a bunch of magic dragon's teeth so that he can free his father.

The J-Team unites to battle the anti-J-Team, and Jade casts a spell that backfires and turns the J-Team into toddlers.

Jackie and Daolon Wong literally race against time to retrieve the Déjà  vu stone, which is responsible for their trip into the past. Uncle attempts to help Jackie from the present as he and Jade watch what is happening through a time window. As Jade watches, she begins to wonder whether she is responsible for all the problems that has been happening in Jackie's life.

Jackie, Uncle, Tohru, and Jade discover that they have overlook something in the ancient writings by making the horrible mistake of placing the final oni mask along side the other eight in Section 13. By doing this, they have released Tarakudo and his generals from the masks that bind them. The entire world begins to be engulfed in total darkness as the shadokahn are now free to walk the earth.