That sounds like it would require the monster to come up with its' own combat tradition, one built on countering one or more other maneuvers from another combat tradition. This is probably why martial PCs are proficient in more than one combat tradition. The better to keep the monsters guessing on what maneuvers your character is going use next.Actually @dave2008 had some interesting takes on improved versions of magic resistance that might be worth a look, if you like the Rakshasas immunity but don't want to spam it to every magic resistant baddie. Did you ever playtest those, Dave? Where's that thread...
What's funny is that having run so much Level Up A5E, I'd almost wish for some monsters that were more resistant/immune to martial maneuvers![]()
...Greater Magic resistance on the rakshasa.
Basically they automatically make their saves. Spells with attack rolls automatically miss.
Magic resistance and legendary resistance often isn't enough. Oys a bit to easy to essentially stun lock bosses with low level spells.
...
If that's the best mechanic in 5.5e, wow, that's...not a great sign.