Responses
Herapi is biologically related to Towa but is not the Dad.
Naguru did say something like 'its in his blood...' or something, but I was not sure if he meant Herapi is somehow biologically related. Though they do really look alike haha
I had a theory at the time when I read this (admittedly it's been a while, I got excited seeing updates again) that the biological mom might be a sister or something.
baby Towa is adopted, when Naguru asks if hirao is the father, it's denied, it seems like hirao picked Towa from somewhere during the storm, and they decided to become family