Isaac Rosenthal

Isaac Rosenthal (イサク＝ローゼンタール), usually referred to as Isaac (イサク), is the 4th generation head of the Rosenthal Family, whose soul was implanted into the Rosenthal artificial soul Taowu.

Etymology
was a biblical figure, the second son of Abraham and father of Jacob and Esau, as well as one of the three patriachs of the Israelites.

is a surname of German and Jewish origin, meaning "valley of roses".

Appearance
In his original body, Isaac had light hair and wore a turban and non-Chinese clothes.

Implanted in the Taowu and possessing the naked body of Hirumi, Isaac occasionally causes her eyes to change color and have slit-pupils, with cracks on her face.

Personality
Isaac shows little regard for human life, murdering many people in order to use their corpses for his techniques. He takes pride in his creations, referring to them as 'works of art', and was displeased when they were compared to 'mere'. He is focused on the Rosenthal goal of creating the perfect golem and is determined to personally accomplish it regardless of the cost.

Background
Isaac was the 4th generation head of Rosenthal Family, who continued the work of their ancestor and founder Obed, who was banished from his homeland as a heretic for developing a method of creating golems from corpses, ending up in the East. Their greatest desire was the creation of the perfect golem, one with a perfect soul and a perfect body - a god, and Isaac was dedicated to accomplishing this goal.

In China, Isaac combined the Taoist Hopping Zombie Spell with the Rosenthals' Kabbalah-based methods of golem creation, developing what would come to be known as Rosenthal-style Necromancy. Isaac continued to develop his techniques in order to accomplish his goal, killing large numbers of people to use their corpses in his work. He held little hope for his son Nathan accomplishing the goal, despite the eventual 5th generation head's creation of four artificial souls with increased abilities.

At one point, Isaac murdered the Li household, using their corpses for his work. When officials broke into the grounds to investigate, Isaac boasted of his 'works of art' before setting his creations on the officials after they made a comparison to.

Isaac continued his work in order to achieve the Rosenthals' desire in his lifetime, but he ended up succumbing to disease. While he was on his deathbed, before his soul could be lost due to death, Nathan transferred it into the Taowu, imprinting it on its artificial soul. The Rosenthal style would continue to develop over the subsequent 19 generations but their ultimate goal of creating the perfect golem continued to elude them.

After Taowu was activated and possessed Hirumi when 23th generation head Estelle attempted to resurrect her following her death, Isaac was contacted by a self-proclaimed demon, who told him of a way to achieve the Rosenthal Family's desire, using a method derived from how the human soul is said to slowly evolve and reach through the process of experiencing 10000 deaths. By converting the memories of death into a special formula and adding it to the sephiroth constructing the artificial soul, engraving the proof of death into the soul 10000 times, their soul would also reach Keter. The memories of death are normally erased from the physical world at death, however the memories of 10031 deaths were present in Academy City, stored within the Misaka Network.

Manipulating Hishigata and DA through the Taowu-possessed Hirumi, Isaac attempted to obtain the memories of death from the Misaka Network, with Estelle attempting to stop them, unaware that Isaac's will was within the Taowu.

Toaru Kagaku no Accelerator
Hishigata was eventually able to obtain the memories via Misaka 10046 and had the formula inserted into the Taowu's artificial soul. With Hishigata dying from a stab wound after blocking Estelle from stabbing the charm, the Taowu ceased simulating Hirumi and Isaac revealed himself after Estelle pleaded for the Taowu to stop. He then began creating the 'perfect body' to house the 'perfect soul'. Frustrated when the process took longer than expected, he consumed members of DA in an effort to speed up the process but was overwhelmed by their desire for justice and lost his hold over the Taowu.

Trivia

 * It should be noted that Isaac (イサク) has yet to be referred to by his full name in the series, by characters or narrative, only referred to by his given name. However it is presumed that the name used in this article is almost certainly correct, given his position as a member and head of the Rosenthal family.