ComandanteIgris

Well it has a really interesting history and some really good characters but it  is a new manga so it has a lot of potential, and one good point is that it is not like the usual isekai manga it deal's with some mature themes so don't expect to be always humerus. I think you should give it a try, at least use the rule of the 10 chapters (read the first ten chapters) . 

For those who dislike heavy stuff like killing you should avoid this manga.