There is a mod i use called "Bad Biters" which basically adds different colored biters and nests with 80% resistances. Basically i like the challenge.
The problem i had is, when i loaded RSO in my map, it started to use RSO biter and resource generation (as intended) for ungenerated chunks, but when i unchecked the RSO biter generation it changed to no biter generation at all. No biters in newly generated chunks. Probably mods overwriting the default settings or something.
Maybe there is or will be a fix for this, thanks
