@matrix Ok so normally I don't spoon feed my down syndrome students but I'll give you this one since it wasn't spelled out for the audience. The souls of the mothers were the secret sauce to the EVAs. Shinjis mom was absorbed by his unit, she would take over and protect him when he would black out from anxiety. Asukas mom was in the unit but because she was a bad mother she didn't help her daughter, Asuka was forced to operate on sheer force of will alone, which EoE illustrates can only work for so long before you burn out. Rei didn't have a mother (or more accurately, her mother was not in her Eva) so hers was essentially soulless - you saw this when it went apeshit when they tried sitting Shinji in it and his suicidal ideation was amplified by the lack of a soul