FormerlyHemlock
Hero
Since half of Vox Machina fought a rakshasa last episode, I took a closer look at the monster... and found it pretty underwhelming.
I mean, it's sneaky as heck, and pretty tough with its immunity to non-magical weapons as well as any spell of 6th level or lower. But it has a pretty glaring vulnerability (piercing damage dealt by a good creature), so-so hit points (110 - on par with the challenge 5 otyugh), and very little offense. Charm person is mostly useless once combat has started, and suggestion is nice but limited and requires concentration. Pretty much the only real offensive move they have is dominate person, and that's a 1/day ability that gives a save to prevent it, and then allows multiple saves to break it. This creature is supposed to be challenge 13. That's on par with a nalfeshnee, or with an adult white dragon.
Back in the day, they had more open-ended spell-casting ability - In 3.5, they cast spells as a 7th level sorcerer which could include some pretty strong offensive spells, as well as the potential for +8 AC. In 5e, they are more limited with their Innate Spellcasting, although it does contain some spells beyond the capabilities they would have had in 3.5e. 1e/2e had something similiar, but with them just having a few spells of up to 3rd level.
Sure, the rakshasa is a great mastermind monster, using its charm, detect thoughts, and disguise self to infiltrate places and take more subtle control of things and people. But challenge rating is supposed to be more about how good they are in a fight - the difficulty posed by the rakshasa's minions are accounted for in the minions themselves.
I'm probably missing something here, but the way I see it rakshasa ought to be more of a challenge 6-7 monster. I'd be way more afraid of a mind flayer than a rakshasa.
I think anecdotal evidence is generally overrated on D&D forums, but here's an anecdote anyway:
I've used a Rakshasa twice so far in 5E. The first time it was while the party was split, and the lone Barbarian (11th level?) wound up fighting the king's advisor without knowing that he was a Rakshasa. Dominate Person was good enough to get the barbarian to Reckless Attack himself (with GWM) almost to the point of death, with a lucky save snapping the barbarian out of just before he would have crit himself to death. (I know this because I had actually rolled both attacks simultaneously, and the second one was a crit.) My backup plan was to either Plane Shift the barbarian to the plane of elemental water (likely drowning him), or to hit him with my poisoned claws ("I" the Rakshasa had used Suggestion to delay him long enough to poison "my" claws with venom from a jar in "my" desk). The barbarian ran away successfully and initiative rolls + circumstances prevented me from pursuing him to finish him off (could have used Fly to pursue but that would have blown my cover, since my cover identity was not known to be a sorcerer of any kind). In those circumstances, the limited tactical depth the Rakshasa has was not a liability: having two or three ways to finish off an enemy is plenty.
The Rakshasa spent the next several days ruining the barbarian's reputation with illusions. Thok was seen consorting with enemy dragons (thanks to Major Illusion) and eating peoples' hearts right out of their chests (thanks to Disguise Self). Rakshasa like to eat people anyway, and getting to blame it on someone you're annoyed with just makes it all the sweeter. Also, he'd scratched Thok with his claws, so Thok spent the next several play sessions screaming in his fitful sleep while other PCs worked to reverse the curse. (No high-level clerics in the party at the time.)
Eventually the party faced the same Rakshasa again--they attempted to ambush him while he was meeting with mind flayers. The Rakshasa played a relatively small part in the combat (illithid Mind Blast combined with Intellect Devourers was the superstar combo) but he was still alive, and unconscious due to drow sleep venom, when the combat was over. No one who was still conscious had any magic weapons, so the PCs drowned him in the nearby river to kill him.
My takeaway from the experience was that Rakshasa is okay-ish in combat, but much better between combats. At-will Detect Thoughts and Disguise Self is good, and Major Image has lots of potential. But in terms of combat power, yeah, it has pretty good defense and not nearly the same level of offense as e.g. a CR 13 beholder. It has decent-ish mobility due to Fly, but that takes concentration so it's not really useful during combat. Overall I'm inclined to agree with your assessment that a mind flayer is more scary than a MM Rakshasa in combat. Adding wizard or fighter levels to the Rakshasa would make it much more scary, if you wanted a Rakshasa that was scary in face-to-face combat. I was pretty okay with it being weak-ish though since I was using it for espionage.