Original sentence: Nina is generally portrayed as emotionless, stoical and focused.Nina is somewhat antisocial, and also appears to be in great psychological turbulence, most noticeably since Tekken 3.She does not smile often, as opposed to her more flirtatious and frivolous sister, but Nina does display a sense of humor where tormenting Anna is concerned.The results of her "cryosleep" (suffering disorienting amnesia), the discovery that she has a son (who was unknowingly created through in-vitro fertilization), and the feeling that Anna is somehow responsible for their father's death, have all contributed to her current mental state.This is presumedly due to the traumatic events of her life: the death of her beloved father (pre-Tekken 2) being the decisive moment that pushed Nina over the edge
Edited sentence: Nina is generally known to be quite cruel and heartless and does not smile often, a contrast to Anna who is portrayed to be flirtatious and friendly.She is cold-blooded and stoic, especially since Tekken 3.The death of her father, pre-Tekken 2, who she loved dearly, has been seen as the decisive moment when Nina became such a troubled person.The events of the cryosleep (where she lost all of her memories) and the discovery that she had a son, whom was created through in-vitro fertilization, unknown to Nina, have also contributed to her troubled mental state.This is presumed to be due to the traumatic events of Nina's life