|This article contains canon information corresponding to the Tales of Arcadia franchise. That means all information in this article is true and has appeared/been validated officialy on-screen.|
In his usual human form, Otto is a slightly overweight man with blue eyes, a large nose, black hair combed back and a light blond beard and mustache. His attire is usually composed of an office suit with a tank top and a pair of round glasses. He has a scar on his right eyebrow.
Otto is initially shown as a fearful inferior who only follows the orders of The Janus Order. Later, his cruel and sadistic side is revealed by betraying Stricklander and letting him die at the hands of Angor Rot, as well as by capturing Jim's friends and pretending to torture them. He has a firm loyalty to Gunmar, pretending to make Dictatious look bad in order to become Gunmar's only counselor.
Otto is a Polymorph and a loyal member of the Janus Order. During the reconstruction of the Killahead Bridge, Otto provides the Eye Stone, the last piece required to complete it. Otto is sent to Strickler by the Janus Order who questioned Strickler's ability to lead them. In his stay with him, Otto accompanies Strickler in the awakening of Angor Rot, as well as questioning the fact of having the killer under control. Hearing Strickler's plans to usurp Gunmar's throne and empower the Changelings, Otto informs the Janus Order that he is only looking for his own glory and not the return of Gunmar as the Order wants. In the end, Otto leaves Strickler and expels him from the Order, leaving him alone against Angor Rot.
After the death of Angor Rot, Otto becomes the superior commander of the Janus Order. When Toby, Claire, Blinky, and NotEnrique seek information on how to revive AAARRRGGHH!!! of the Creeper's Sun, they discover Otto and decide to follow him to The Janus Order who possess the antidote to save him. However, Otto's abilities manage to confuse them. When the group finally discovers The Janus Order barracks, Otto manages to use his Polymorph skills to trick them and capture them. There, he offers to give them the antidote in exchange for Vendel's walking staff, which they are forced to accept. The deal takes place and Otto gets the cane with a part of the Heartstone. When Gunmar finally manages to escape from the Darklands, Otto receives him and gives him the staff so that he can recover his strength. Otto takes Gunmar to The Janus Order and helps him in the process to retake his power. During that time he usually has friction with Dictatious for Gunmar's favoritism. Eventually, Dictatious overhears Otto complaining over the Janus Order not hearing anything from the Pale Lady since Gunmar's return and pretends to be the Pale Lady's seer to gain favor with Gunmar. When Gunmar decides to eliminate the Janus Order and take Troll Market, he puts Otto under his control (due to his Polymorph abilities) and uses him as a diversion to get the Trollhunter away, forcing him to use his Polymorph powers to take his form. Otto is finally killed by the Sword of Daylight and Gunmar uses his body to reveal that all had fallen into his trap.
Being a Polymorph, Otto is not limited to a single false appearance like the other Changelings, since he is able to change at will to the form of any human or troll he desires without the need of a Familiar.