[quote=@Primal Conundrum]
[@Sombrero]
An interesting take on the Illithid concept! There are two concerns I have, but they're just that: concerns. And concerns can be addressed and resolved.

First concern (and the lesser of the two) is that I don't know if it'll be a nautical / piratey campaign. That's easily dealt with though, as a compelling character will work on land or sea. Also, if we end up doing much in the way of vehicle combat, you could go for the mounted raider theme instead which is essentially a pirate on land. Easily solved.

Second concern, and this is the one where the ball is more in your court, is that Illithids are traditionally pretty powerful creatures. With a whole pile of psychic nastiness plus more combat ability, compared to the other options it feels really strong. However, like I said, I'm totally into race tweaks, so if you have an idea for how to bring Illithids closer to the baseline of power while still retaining their style and flair, it would be a character that I'd love to have on board!
[/quote]

Well, in lieu of the first thing, my aim was generally to make him more of a viking-ey pirate, since he'd be wearing more fantasy armor and getting involved in melee/land combat anyway for the sake of having more land, but I'd totally be up for making him a Mad-Max villain with a roving band of brigands in a big, ship-like Fantasy Vehicle, because that's freakin' amazing.

My idea is that Illithids have glands that secrete... Midi-Chlorians, by any other name, and these glands can be "exercised" in order to produce more of them more often. (I imagine they give prisoners of their ilk hormone-suppressors instead of handcuffs, so they can't brain everyone to death.) Now, most Illithids, when made/born/hatched, will have other Illithids with them/will be brought into an Illithid society that can teach them how to use these powers and better exercise their minds, but, since this guy got really pissed and killed the one who infected him, he doesn't have that luxury, so what powers he does have he had to find and practice on his own before they could come to any practical use, and he's never set much time aside for strengthening himself in the ways of Mind-Flayery. So, if he's met with another psychic, or someone of above-average willpower, he'll have to try and match them on psychic grounds with either stubborn persistance and/or surprise, or give up and get his sword out.