Anyone have good ideas for Ultroloth stats that don't have anything to do with the weak stats from the MotP and MMIII?
Somehow I was thinking of giving the Ultroloth some abilities like the Warlock, since I actually like it when monsters have class abilities rather than some random collection of spell-like abilities.
Just use the standard CR 13 version, and either just add warlock class levels right on top, or, better yet, take the base race and give it the abillity to invoke and use Eldritch blasts as a Warlock. Sort of like how Arcanaloths have integrated sorceror casting. Either way, you should probably keep the Challenge Rating at less than twenty, so that it matches Balors and Pit Fiends. Plus you don't want its CR to be too high, because games rarely continue after level twenty (which has more to do with the totally nonfunctional epic rules than anything else).