Responses
The Big Sis he mentions in chapter 197 is Isis, that's his nickname for her. We know it's her because he says "how does my sis do it, should I get a staff too??" and the only woman with a staff whose power he respects is Isis. He's been awed at Isis' power to conjure lightning with her staff since chapter 66. In chapter 68, we saw him pester her to tell him how she does it.
So with the lighting, is our sexy mystery god zues?! But then he mentions an "older sister" and if I remember correctly Hera is their sister as well. Cause he mentions his siblings and the medicine, so could this be around the time with Kronos and the Greek gods fighting the titans?! My mythology adhd is going crazy