Kraken is the final antagonist of the book series, Unicorns of Balinor. He is powerful with the Deep Magic, and is the dark counterpart to the Old Mare of the Mountain. Both are seldom seen. Like Entia the Shifter, Kraken possesses shifting magic. He is seen taking the form of a giant spider, a hooded figure, and in the eighth book is described as having a skeletal hand.
In the fourth book, Kraken appears as a mysterious servant of the Shifter called the Shadow Rider. His true identity was not known to Entia, leading him to believe that the Shadow Rider was under his control when in reality Kraken is even more powerful than the Shifter. Riding the lead Shadow Unicorn, Moloch (called Moloth in the fourth book), the Shadow Rider raced against Arianna in the trial by fire, to which Arianna and her unicorn, Sunchaser, won, slamming a door in the Shadow Rider's face.
In the sixth book, the Shadow Rider appeared before the Shifter again. He grabbed Entia's horn while he was in unicorn form, causing him pain for the very first time, proving himself to be stronger than him and giving him ominous warnings.
In the seventh book, after Ari took back the Royal Palace from the Shifter's forces, Kraken revealed his true identity to Entia. Although Kraken was on his side, he was not pleased with his failure, as the Royal Scepter and the Indigo Star were both taken back from him. Kraken threatened to kill Entia if he lost the upcoming war, and blocked his Watching Pool. In the Battle of Balinor, the Shifter's army was defeated by Ari and Chase, and Entia was killed by Numinor and the Celestial Unicorns. The Shadow Unicorns fled the battle. Castle Entia and the Valley of Fear were destroyed, and Kraken's hand rose up from the ground.
The dark magic seemed to weaken with the Shifter's defeat; Kraken was trapped below the surface of the earth, and Moloch was forced to take the form of a crow. When the comet from which Kraken got his power drew near, Kraken became stronger. He would also grow stronger if Ari used the Royal Scepter. Eventually, Moloch reassumed his unicorn form and fought Chase while Ari confronted Kraken as his hand reached out of the ground. When Lincoln, in his true toad-like form of Gully, distracted Kraken, Ari directed the power of the Scepter to the comet, taking away its power and causing Kraken to wither to nothingness.
After Kraken's defeat, Chase defeated Moloch, who surrendered to him, and at Ari's request Chase let Moloch escape.