It's kind of annoying that Rimuru owes his life (and the lives of many friends) to Great Sage/Raphael, but he's still constantly ignoring her, despite having previously already paid a price for doing so. It weird how he has such a cheat power at his disposal, but doesn't really respect her, at the end of the day. I guess that's what happens when you were born (or reborn) with vast powers and thus take them for granted. Sure, he has has displayed token gratitude occasionally, but it feels pretty superficial when he otherwise only deigns to listen to her when it suits his mood.

Of course I know that's not the case in reality, it's just the ages old case of an author writing himself into an inescapable trap. Raphael is totally broken, so the author regularly makes Rimuru ignore her for the sake of what goes for a plot in this story.

It would have been interesting if Rimuru had fought seriously against Milim, but I guess it's understandable he wouldn't want to do that. At least Veldora got a good tone rocked out of his dome.