From the manga/anime series Soul Eater, Professor Franken Stein is a powerful Meister capable of sensing and using spiritual energy for attack and defense. He is also a teacher hailing from the Death Weapon Meister Academy, with a desire to understand how things work around him through either observation or dissection.
Commonly referred to as Professor Stein, Dr. Stein, or simply Stein. As with his original incarnation, Stein struggles with maintaining his sanity and is exceedingly dangerous during his bouts of madness.
As with his abilities in the original manga and anime, Stein is capable of percieving souls of other individuals through the use of Soul Perception. He is also capable of utilizing his own soul's resonant energy to attack other souls, the effect much like being shocked with electricity. Though not used much in BLN, Stein can change his own wavelength to nullify the effects of a soul wavelength attack from an outside source and wield any Weapon that is available for use or aid.
Under a state of insanity, Stein is able to take far more damage than normal, his attack output also rises to maximum capacity. He will focus exclusively on a singular target during this period, attacking tenaciously and without quarter.
His state of insanity can usually be remedied through two methods. One is by turning the screw in his head until it clicks, the other through mild electrocution. While both temporarily stave off his insanity, the screw method lasts longer than the electrocution method, and is also a less life threatening alternative.
Aside these attributes, Stein is still human and can feasibly die in certain circumstances.
Though Stein seems standoffish at first, he feels obligated to help when he sees someone needs it. Often the voice of reason or assessment, he has a calm demeanor which is present even during highly stressful situations. He has an idea of what is right and wrong, however in instances where science is involved his morals slightly skew towards being morally ambiguous.
Stein is usually laid back and observant but sometimes can prove to be quite silly in actions or statements. However, he does not fully grasp the idea of societal norms and struggles to understand empathy and sympathy. He attempts understanding of these, despite a desire to toss them away, simply because he does not enjoy himself if he stops trying to care.
This results in Stein having faint, but strong, relationships with few people who he considers 'important' to him. He has only ever admitted to genuinely caring for Marie Mjolnir on a personal level, but he has admitted to valuing his vitrolic friendship with Wade Wilson.
During bouts of insanity, Stein is either completely calm or utterly ecstatic depending on the situation. He is incapable of being reasoned with during that state and only focuses on a singular target eligible for dissection. Even during sane moments, Stein has an utter fascination with taking things apart to see how they work and is a sticking point in his insanity.
Much of Stein's past is borrowed directly from the anime series of Soul Eater, though his arrival to BLN came during the expulsion of Grell Sutcliff and Medusa Gorgon from the Wayne Estate . Stein arrived to the area through a reality nexus, though prior to finding the mansion he had been wandering aimlessly through the nearby woods.
Shortly after his arrival, Stein assisted the household of the mansion in repelling another attack of MA. The fight progressed into a battle between MA's 'Form' and Stein exclusively, the professor displaying amazing prowess and power against the creature himself. To seal MA away, Stein took Crona's place in offering a deal with Nya , which agreed to let her take what she wanted. The subsequent deal, ambiguously phrased and worded, readjusted Stein's fate to lose his ability to regain sanity on his own, resulting in Crona relocating him in the wilderness and out of harm's way.
Stein originally was sent by Shinigami-Sama or Lord Death to the manor to keep an eye on Crona, tasked with the responsibility to kill the Demon Sword should he regress into a Kishin. This only happened once, but he was summarily stopped by other mansion residents before he could reach Crona. While Crona ended up not becoming a Kishin, he and Stein share a strained relationship with this arrangement over their heads, both acutely aware of the consequences should anything be pushed that far.
Stein's friendship with Deadpony engenders from a seemingly random fight, where Stein utterly floored Dead with superior fighting strategy and technique. Afterwards the two became aquaintences and finally friends as time passed. Stein acts as a foil to Deadpony, or Wade's, erratic personality by being calm, collected, and logical in comparison.
He is notorius for his attempts under the influence of insanity to focus on dissection of pegasai in the estate. Shy Assassin, Starky, and Daring Dakota Do all at one point where in danger of becoming his latest subject because of their extra set of limbs. However, he had never successfully managed to dissect a single pegasi, leading up to what is a BLN running joke.
Outside of his dissection preoccupation, Stein has constantly struggled with his Madness throughout BLN. During the Asylum arc, Stein was psychologically reconditioned to losing himself automatically to Madness by a passphrase Professor Strange created, which was used in tandem with the then-AI of the institution HAL to weaponize Stein. Following HAL's defeat and retaking of Asylum, Stein was restored to full sanity, which he retained for nearly six months. However, the effects were temporary and Stein once more had to live the daily life dealing with his own Madness issues.
Currently, MA is a figure whom mentally challenges him to break and lose himself entirely to his insanity. Stein currenly tries his best to fight this inclination because of the damage it would do to his relationship with Marie, as well as a personal promise he made to himself following the creation of Boo at Asylum.