Kurama

He is the chief of research, aged in his mid-30's, of the diclonius children in the research containment facility. He is also the surrogate father of Nana and biological father of Mariko. His wife, Hiromi Kurama, died from Caesarean section complications shortly after she gave birth to Mariko. Although he had previously been tasked with killing all diclonius births, he falters when he must kill his own daughter. Lucy carries a deep hatred toward Kurama, stemming from his failure to save Aikon Takada (seen in the Elfen Lied OVA); however, she states that she will not kill him but will kill everything that loves him.

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(Source: Wikipedia)