Sid was truly a good person the parasites in him just had too much control I feel he just wanted to be loved and needed like how the brown hair dude loved the doctor. sid struggled to understand the true meaning of love and it made him who he is I feel that the little love that Metatron gave him truly changed a lot inside him causing him to act this way and sacrifice his life for Cain and help the human in the other chapter Sid truly is a misunderstood character who struggles to understand his own emotion (I'm sry for making this paragraph)
I'm BBN rn (meow)