Jozaysmith?
He/Him- 2,420
- 530
Agree with this but the match isn't even an official one its a friendly matchThe Great Sage always takes the best option after analysis, if he decides that becoming an SL is the best option he will abandon his physical body, as he has already done during his training when testing his abilities during volume 2.
In another scenario Rimuru could enter in Battle Mode, where the Sage takes control and based on analysis chooses the best alternatives.
As for surviving as a soul, Spiritual lifeforms can fight as such, albeit at a higher energy cost.