Some ideas that might help flesh him out:
* Not only having a low int (which I like to think of as "memory" and "reasoning", but he's also got high wisdom (which I consider "intuition" and "willpower"). In general, he doesn't know what to do (whether he thinks he does or not), but he knows whatever he's doing is correct. When faced with a decision, never consider, never weigh options. Go with what gut feeling your character would have.
* He's also a rustic wild elf that "don't get out much". His personal interactions should be direct and sincere (no politics), and his social interactions should be horrifing. Consider how he'd act at a formal dinner party, with this slew of trite superficial manners and unwritten rules, he'd be so offensive it'd be a miracle if the party survived through the night! Again, this stems from his upbringing combined with his low ability to recognize and adapt to different settings. A human raised in cities with the same ability scores would act better or at least understand the difference between formal and informal social interaction. On the other hand he may be the spokesperson of the party if they're in the middle of nowhere trying to work with a tribal village, whereas in the city the party is on the verge of chaining him up.
* He's probably literate, but woe unto the person who has to read what he writes. And english (common, elven, ...) professors should have a heart attack if they hear him speak. Don't use bad grammar when speaking, use
offensively bad grammar. Any time he has something very worthwhile to say (coming from his high wisdom), it should sound like the worst idea ever simply because of the way in which he expresses it. It'll make his insight that much more spectacular when the party figures out what he means.
* Back to the rustic idea, money is probably a cute formality that he tries so erringly to mimic. His high wisdom lets him understand that people are passing materials around as some sort of currency for return goods/favors. However his low int combined with his race (wild elves are skeptically familiar with this notion of "towns") spells disaster when he tries to use this whole money thing himself. Have him carry around buttons, shiny fish scales and other worthless paraphinalia(sp) to hand off at the most inopportune times when talking with people, etc. Eventually he may catch on or even just give up on trying, but it should be a comedically painful series of trial and error.
* In short: He has great intentions, but poor delivery.
* This sounds like a really fun character to play

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