An Aquatic Beast Man Digimon that has taken the form of a woman, it was discovered in the deepest trenches of the Net Ocean, the birthplace of Digimon. Thetismon brings peace and tranquility to its own vast territory and lays down the law on any Digimon that dare to disturb it. It has an ingrained need to help the weak and weaken the strong. As such, while it shows no mercy to Digimon who threaten its territory, it is kind to those in need of help, guiding them to safety.
Thetismon eliminates invaders with special moves like Biri Smasher, a technique in which it utilizes electrical energy accumulated in its palms to send its fists flying, Hammer Thunder, which involves kicking an enemy up and then bringing it down with the force of two electrically-charged fists, and Adue World, which allows Thetismon to teleport by removing the space between it and its opponent.
Finally, there is Dokutease, in which various medicines are generated and released from its tentacles. With this ability, Thetismon can heal allies' wounds and temporarily boost their powers. If used against an enemy, however, it will afflict them with a deadly poison that disintegrates them from the inside out.