Satori Amatsu

Amatsu Satori is the main character of the My Vampire Older Sister and Zombie Little Sister series.

Appearance
Satori has short black hair and black eyes.

Personality
Satori has a strong desire to help humans and Archenemies get along. Even as a child, he was willing to suggest that a vampire and a zombie bite him so that they could be friends. As a teenager, he is prepared to take on the powerful Bright Cross Disaster Prevention Foundation in order to stop its oppression of Archenemies.

By his own admission, Satori is a pervert. He is mainly interested in his childhood friend and next door neighbour, the Class Rep, to the point of creating a virtual model of her that wears a swimsuit and dances. He also shows some interest in other girls like his stepsisters, but not to the same extent as the Class Rep. However, like many other harem protagonists, Satori is unaware of any of the girls interested in him. For example, he disregards an invitation by Erika to do what he wants to her unconscious body.

Background
When Satori was a boy, his parents began to fight (over the father's job at the Bright Cross, though Satori didn't know that at the time). Satori put on a smile to disguise his feelings, but he would look sad when no one else was around.

Satori used to have a group of friends who maintained a secret base beneath a bridge - a space made of cardboard boxes and galvanised iron sheets. One day, when he visited the base to clean it, Satori found two girls there: Erika and Ayumi. They asked to borrow the base at least until sunset, as Erika needed to stay out of the sunlight. Satori decides to bring them into his group of friends and opens up to them, eventually revealing his worries about his family. They ask him what he would do if they were a vampire/zombie.

Eventually, Satori's parents divorced. His father remarried, with his new wife Yurina Amatsu bringing Erika and Ayumi along as stepdaughters. Satori initially had difficulty getting along with her, to the point that he called her with the distant form of address "Yurina-san". This ceased to be the case after one parents' day in which Yurina's presence improved Satori's standing at school.

With the help of universities and research labs, Satori managed to build the supercomputer Maxwell. During the construction of Maxwell, Satori regularly posted about his work on his blog. He then used Maxwell for a range of purposes, including simulating the Class Rep dancing in a swimsuit and simulating alien invasions and wars between giant robots.

Volume 1
While in the same room as his sisters, Satori has a conversation with the Class Rep next door. Class Rep mentions that she'll be watching a movie about a showdown between two types of monsters, causing Satori to wonder out aloud whether a zombie or a vampire would win in a fight against each other. This causes Erika and Ayumi to try to answer this question by starting a pandemic (each believing that their own species would win). They demand that Satori let them use Maxwell to simulate their fight. Satori refuses but the sisters threaten to reveal his use of Maxwell to simulate the Class Rep dancing in a swimsuit. After the sisters enter the simulation, Satori learns from Maxwell that if the Class Rep dies in the simulation, data on her (including the Swimsuit Dance File Set) will be released to others. Satori tries and fails to cancel the simulation, with Maxwell explaining that the sisters have equivalent administrator rights to Satori and their superhuman parameters have caused the system to be in too much chaos to accept outside commands. Satori is left with no choice but to log into the simulation as a normal user in order to protect the virtual Class Rep.

Abilities
Intelligence: Satori is extremely intelligent, and not simply by the standards of a high school student. He was able to build (albeit with help from universities and research laboratories) the supercomputer Maxwell, which is capable of simulating the effects of disasters on an entire city. He is capable of formulating strategies to fight a wide range of Archenemies (and to allow others to fight them).

Artificial Intelligence: Satori has access to and the loyalty of several artificial intelligences, either building them himself (Maxwell) or obtaining them by other means (Laplace, Ghost Cat). Anti-Materiel Redtooth: This is a device that uses a powerful electromagnetic signal to send illegitimate data to electronic devices in order to jam them. It has a range of 1000 metres.
 * Maxwell: Although Maxwell's "body" is too heavy to carry around, Satori maintains contact with her by using his smartphone. At Satori's instruction, Maxwell can easily hack into most computer systems to perform feats such as: stealing information; modifying information; operating machinery (up to an including an entire cruise ship); and forcing machines to function in ways not intended by their designers (such as causing the lithium batteries of smartphones to detonate with enough force to pierce human bone). Maxwell can also analyse an enemy's fighting patterns, including both martial arts techniques and the ballistics of projectiles, and thus predict them. Finally, Maxwell can use directional microwaves to remotely communicate with someone by vibrating the lymph fluid in their eyes.
 * Laplace: Laplace originally had processing power vastly superior to Maxwell. In its first appearance, it could shift the aim of the powerful Valkyrie Karen and provide enough of an opening for Satori to mortally wound her. Afterwards, its specs are significantly lowered (to slightly below Maxwell) due to Satori only being able to retrieve a portion of it. Laplace is slaved to Maxwell to boost the latter's specs.
 * Ghost Cat: Ghost Cat has inferior simulation capability compared to Maxwell or Laplace, but is superior at controlling unmanned weaponry. It is slaved to Maxwell to boost the latter's specs.

Giant Garlic: A unique form that Satori assumed in a simulation by the Ghost Cat. In this form he is a garlic the size of a human head and retains the standard five senses despite lacking sensory organs. He can move around by rolling and can even jump. He has the same strong odour as normal garlic, which may attract unwanted attention.
 * Duplication: Satori can split himself into eight identical garlics when exposed to soil, water and sunlight. His consciousness remains in one of the garlics, but he can receive sensory input from and control all of them. If the garlic his consciousness is currently in dies, he "jumps" to another garlic. Each duplicate garlic can repeat the process and there appears to be no hard limit to the number of duplicates he can have active at the same time, but once the number reaches 300 or so it becomes difficult for him to control them.