It is seen in the series that the Mystics are powerful enough to even outmatch the Ninja Tribunal. They are called "Heralds of the Shredder" because they were loyal servants of the true Demon Shredder. They were first seen in the series as guards of the Utrom Shredder because they were being controlled by the Heart of Tengu. This artifact is demonic and holds the commands of the Mystics. The Utrom Shredder somehow knew this and took advantage of it. In , the Mystics awaken when the TMNT and Splinter attempt to infiltrate the Utrom Shredder's tower. The Mystics outmatched the TMNT, until Splinter used the Sword of Tengu against their foes, using the elements the Mystics were composed of against each other.
In Ninja Turtles on an astral plane. It is also said the Utrom Shredder had more respect for their power than Karai, but she cold heartedly tells them that she does not respect them and as long as she had the Heart of Tengu, their powers were hers to command., it is revealed that the Foot Mystics have black magic powers, when they launch an attack against the
As a result of their mistreatment at the hands of Karai, they became more determined to liberate themselves from her, and after tricking Bishop and the ninja turtles by proxy, into stealing the artifact, while the Mystics themselves allowed them to pass into the new Foot Tower. The Mystics broke free of Karai's grip when Baxter Stockman destroyed the artifact and they began to attempt and resurrect the true Demon Shredder. When freed the Mystics were able to revert to their true forms and were shown to be far more powerful then previously shown.
The foot mystics are the main antagonists of the first part of the season, trying to resurrect the demon Shredder by having monsters guard the parts of his dead body. After all 3 artifacts are recovered by the acolytes and the Ninja Tribunal, the Mystics take matters into their own hands. They kill the Ninja Tribunal, as well as the 4 other acolytes that the turtles had befriended, and stole the three artifacts. They retreated to New York, but were followed by the turtles, Splinter, and the Ancient One. Despite their fanatical devotion to the Demon Shredder, they were still abused by him for so much as saying anything he felt was out of line. Especially when they plead for their master to kill Karai for "stealing" his mantle, which doesn't concern him the least, much to their displeasure. It was later revealed that they were disgusted at serving Ch'rell and hatched a plot to resurrect their master by using an invisible bone demon to gather the helmet, gauntlet and body from the "Ninja Tribunal", but it was defeated by Master Splinter and the Ancient One. It was also revealed that the Mystics at some point in time sent out there demon servants to steal the gauntlet and helmet from the Tribunal and when they arrived in Japan they found their servants defeated by the new acolytes of the "Ninja Tribunal", who were in fact the Ninja Turtles and four other brave warriors chosen by the Tribunal. After a massive attack the Mystics succeeded in recovering the Demon Shredder's helmet, gauntlet and body and eventually revived the true Shredder. They are all killed in "Enter the Dragons, Part 1" by the Turtles, the other four Acolytes, and Karai.
In the Fast Forward episode , the Metal Mystic in his original form appeared before Raphael and Casey Jones following their fight with the Purple Dragons and teleported them to a deserted island for three years. This was found in one of the pages of Casey and April O'Neil's journal that the Turtles were reading despite Splinter and Cody's warnings not to read it. However, this particular event was a complete fabrication by Master Splinter and Cody in order to teach the Turtles a lesson about messing with the future, though this was only because the former got tired by the end. Splinter even found the part with the Foot Mystic to be humorous.
It is implied that whilst under the control of the Utrom Shredder and Karai, the Foot Mystic's powers were weaker than when they were in their true forms. Nonetheless, they were still impossible to defeat through physical skill alone, requiring the powers of the Sword of Tengu, or skilled meditation, in order to be beaten.
Individually, the Mystics have powers and abilities which are related to whichever element they represent:
- The Metal Mystic, who controls metal can form blades that can stab or tear enemies asunder, create liquid metal, and metallic dust.
- The Earth Mystic is larger and more muscular. He can create sand that blinds or overwhelms enemies, hurl large boulders, form fissures, and tunnel underground.
- The Fire Mystic is the leader. He can create large flames and fireballs that packs a burning touch and explosive power.
- The Water Mystic can make waves of water and giant bubbles that submerges someone and drown them. He is also capable of creating walls of ice as well as freezing.
- The Wind Mystic is the most agile and flexible. He can conjure powerful wind currents such as tornadoes and can dodge many attacks and is shown to move faster than other beings. Although all of the Mystic Ninjas can fly, the Wind Ninja is the fastest while in the air.
The Foot Mystics' combined powers also let them create extremely realistic illusions in the minds of their enemies, although Master Splinter managed to see through them. Other magic also lets them fly, project lightning bolts, disguise their appearance, observe others and events from afar, speak to others on electronic frequencies, cast protective shields, and teleport themselves.
In their true forms, their powers increased to such a degree that they are able to summon and command demonic creatures and outmatch the mighty Ninja Tribunal in combat.