This is the shittiest manga i ever read. The author is really lack of responsible as a storyteller.
Conflict is always there in real world, and he avoid answering the question whether Rimumu decision is right or wrong by magically resolve all the fuking conflict with shit that he pull out of thin air.
Why bother to tell a story that doesn't resolve any conflict it present?
For those who didn't get it, imagine i tell you a story about the struggle of a poor family. Then after present struggle they facing, now they need to decide whether they need to steal to survive or wither away like other poor people. The answer? Magically get 1 million dollar, it sound impossible but there is a fairy tale said it could happen. So the family brought into that story and get 1 million dollar..happily ever after.
But if that happen to everyone, no one will be poor. Why bother to tell an unrealistic story about poor people anyway, they don't exist in author world.
Just like this slime story, no one can die in this world. No threat is that is too great that they cannot handle. Introduce a "Disaster" or "Calamity" enemy and the best they can do is blow up some houses. Such a waste of potential.