I go to a Special Quest Bed(and I can do it since there's one in the Underworld) or whatever, somehow die in the Underworld while on top of that bed, and some incarnation of me ascends to the God Tiers. I fly/warp/whatever to where Bop is and fight him. Before starting the fight I ask him why he antagonizes me?
I can separate my spirit(even though I said soul, not spirit) from my body, once my life on the body has gone too far, like if it were valid for death. Besides, you don't banish bodies to the underworld, only spirits. And since we can fuck logic, I can die in the Underworld. I ascend to the God Tiers in some body, probably the previous one I used which is banished in Pluto. I destroy whatever stops me from getting out of Pluto/the Underworld/wherever I am now. I go to where you are and ask you why you antagonize me before you fight.
Off-topic: Why are you antagonizing me so much in this game? Seriously.
Fine. I GTFO your way so you do whatever you're going to do without me stopping you and go on my own searching for what to do. I meet with Bob Jason again, I guess.
You cast the dark magic on the thugs. Realizing the mysterious deaths, the town soldiers investigate and slice off your head. You are now in the underworld.