Heck even kobolds. Almost every wizard character I play takes Speak Language: Draconic just so I don't have to kill the poor little lizards. They're cute in an uncivilized way.
Remember, that horrifying monster is destined itself to be eaten by the elder brain. What's worse, being an aboleth that's evil because you were born with memories and a personality that has existed since the dawn ages, or being evil because your entire existence is a tortured joke.
Honestly, this is just an indictment of the health care system in the Forgotten Realms. Mindflayers should control a powerful lord to mandate universal healthcare and improve the supply of potions and employ cleric healers throughout the realm.
Now, there is room a plot-twist, where the PC hear about a monster looking for healing potion for his brother, and who murdered their father. Monsters have feeling too, and adventurer are awful murderers
Assuming that their victim will seek for revenge and that authorities will hunt them is a good way to force murder hoboes to calm down
Or a good way to cause the normally not murder hoboes to genocide their entire race for merely existing. Every wizard I play takes a ton of languages because I end up with more SP per level than rogues, so by the time the DM is throwing Mindflayers at us, I can speak to basically any intelligent creature, in their own language. I'm a walking peace treaty waiting for a place to happen, that just so happens to have DBF spells just in case. Mindflayers and Aboleths are Kill On Sight. I'm not daring to piss off the gith in any way, those guys are cool.
My level 17 wizard took out multiple mindflayers, solo. I needed the rest of the team up until then, just to be sure I wasn't being overconfident, but I happened to have a scroll of Wish that I copied into my spellbook, and I took Unfailing Missiles, and Mind-rape, (for counter spelling purposes only. I don't play evil characters,) as my level 17 spells.
Unfailing Missiles was designed by me.
Level 9 Wizard Spell
Components: V, S
Casting: duration: instant
Range: Long 400' + 40' per caster level. (1080' @ Lvl 17)
Unfailing Missiles gives the caster 3 "lances" of energy that may be directed at any three targets that are no more than 20° apart. The caster can also direct multiple lances at any single enemy. Each lance does 17 d6+1 points of sonic and force damage split 50/50. There is no saving throw. If you can see it, it gets hit.
I was a bit irritated that Magic Missile was the only spell that was guaranteed to hit. The DM capped the spell at 17 d6+1 with no level scaling because he was already having difficulty designing encounters that the group was having any difficulties with. He did allow the range to scale normally, so with magical glasses I could eventually hit shit at well over a quarter of a mile.