The relief in that last page is palpable, the adrenaline rush followed by your body slowly getting loose and heavy is very felt. I hope Walm is able to rise back up and become a leader with new subordinates.
Great way to end the chapter.
Personally I enjoyed the MC sparing him, death is too easy for evil people. They should live with their sins and forever be tortured by them.
Plus in storys this allows them to potentially come back later.