this entire conversation is very important to understanding their relationship, but like. This specific moment. this part is like when everything clicks, if you get what i mean. Like.
"try not to take pity on the princess. she is already knee-deep in a bloody swamp; even if she wanted to turn back it would be equally as difficult."
in comparison to otto and his obsessive nature with his relationship with kallen. him literally saying try not to take pity on someone like that, to bianka, who doesn't remember her past memories before being saved.
otto and him purposefully withholding the information of her true identity, as she had told him her new chosen name. having her start anew as bianka, rather than telling her the truth, leading to her joining schicksal at such a young age and coming to trust otto and view him as a mentor and father figure because he was one of the closest people to her as she was recovering. kira even says at one point that otto treats her differently than when he's with other valkyries. which makes you crazy when you remember. Everything.
"but please believe in one thing: there are more kind hearted people than there are bad people."
and she grows up to believe he is one of the kind-hearted and good people. su even confirms it during second key:
"otto apocalypse, the overseer of schicksal... so this is what /she/ thinks of you."
"people treated otto as a schemer... yet bianka views him in a positive light."
and the fact that su had saw all of her past memories. so he Knew.
