Josef Mengele experimented with thousands of mice when he worked on his doctorate in medicine. Vivisection, behavioral studies, and surgeries were his favorite experiments on the mice. Otto, and his litter mate Fritz, along with another mouse who the doctor called Ursula were the only survivors. These three, which Mengele call his "Drei Blinde Mäuse" or "Three Blind Mice" were special to him. Mengele, who was later to perform even more gruesome experiments in the concentration camps. The mice became the prototype for his experimentation in the subject of forced mutation.

However, when Josef graduated from medical school, he promptly forgot about the mice, leaving them in his secret lab. This may or may not have been his intention, because Otto's powers were quickly developing; Otto might have influenced Mengele. With the assistance of Fritz, who's telekinetic powers were burgeoning as well, the three mice escaped their confinement.

At first the three confined their interests to survival. Fritz protected the three against threats that got past Ursula powerful mental illusions. The three stayed at the medical school learning more and more as the years went by. It was Otto who first noticed that Mengele had retarded their aging some how. However, it was the Allied bombing raids that forced the mice to abandon Germany.

Over the years the three mice have travelled the world over, rarely staying in one place for long. Survival still was their major concern. However, even survival became secondary in their goals. Otto grew convinced that with their powers they could take over the world, and make it work for them. At first Fritz and Ursula were reluctant; they had never used their powers on a human before.

The mice returned to Hamelin, and experimented with homeless people. Otto's plan seemed to work without a hitch. It wasn't long after that the Drei Blinde Mäuse were running the city, Otto mentally controlled most of the policitians, police, and criminals in the city. And who would suspect three little mice running everything. These mice weren't so blind after all.

Otto has always been the leader of the mice. He wouldn't have it any other way. So far none of the other mice have challenged him in the past sixty years. Besides Felix is very much the follower, and Ursula isn't the brightest of the three. However, if either one stepped out of line, Otto would correct them.

Otto has also found that he really enjoys mentally controlling others. Since Otto can not only control animals with his mental powers, but humans as well, his world has grown dramatically. Otto doesn't think much about invading others' minds. To Otto it is all second nature. Those who resist generally will be punished by the head mouse.

Otto also thinks he knows best. He has guided the other mice for many years, and it through his leadership and his meticulous plans they've not only survived, but thrived in a world where everything is bigger and generally more lethal than they are. Otto always has a plan in place for their continued survival, and if that plan doesn't work, Otto always has another plan waiting.

"The more we do to you, the less you seem to believe we are doing it."

For a mouse, Otto is a mental giant. His mind is so powerful that he can seize control of another mind, be it human or animal, it doesn't mean a difference to Otto. Otto is also able to read others thoughts, but not as powerfully as he can control minds. When angered Otto is also able to cause a painful mental inballance. Otto also has a minor telekinetic power that causes a field of energy to form around him that protects him from attacks.

Otherwise, Otto is a mouse. As such he's often times hard to see, let alone hit with an attack. His small size allows him to be incredibly sneaky, and can easily hide in plain sight. Otto's mousy eyes are quite sharp, and he can even see in the dark. On the negative size, due to his small size, Otto can barely pick anything up, and his short legs means he doesn't run fast. He usually relies of Felix for transportation.

Otto, like Fritz, and Ursula is a small white mouse. Physically he's indistinguishable from any other lab mouse. However, mentally he's a giant of a mouse, even radiating an aura of mental power. Naturally only those attune to mental powers can detect this. Otherwise Otto has a short pink tail, and his paws are pink as well. Otto likes to stand up on his hindlegs to get a better look at the world.