We’ve all created at one point a character who’s mental abilities are… shall we say below average, their power in intelligence and wisdom (or wits or what have you) diverted to more useful pursuits. But how do you actually roleplay such a ‘simple’ character?
Simple characters often get played as a stereotyped nitwit, with bad grammar and an overly aggressive attitude. But while this can be funny for a bit, the jokes about “me not understand, me smash” get old after a while, and from an out of game perspective give little incentive to their party members to keep them around. After all, why would you want a buffoon in your party, even if he deals a lot of damage?
For a more well rounded character, consider not just the limitations these characters have though, but also how they would naturally work around them.
First off, simple characters don’t give up in the face of adversity. As their “brilliant ideas” fail most of the time anyway, they are well experienced with hardship and setbacks and have thus learned to keep going regardless (or perhaps “not learned” to stop). In some this manifests as grit and toughness, in others as Pollyannish optimism and in some as indomitable faith, but whatever form it takes, it is a solid foundation that more labile party members can rely on.
Secondly, while these simple characters may not know why their plans fail, they are at least capable of noticing that they fail, if only by virtue of not reaching the desired outcome. So when they then encounter someone smarter than them who advises them on what to do, they can likewise see that by following that advise, they do reach their desired outcome.
Following the advise of others without fully understanding the consequences is not without risk, and simple characters have likely been taken advantage of in the past. Often many times over. This makes them slow to trust and as a result, ironically, often less naive then their intelligence would suggest.
Moreover, when they do find someone who genuinely has their best interest at heart — and who’s advise they can consistently rely on to bring good results — it is a game-changer which has a huge impact on their life.
While usually not blindly obedient, they have learned that while they may not understand whatever plan their friend, (or lover, boss, etc.) has come up with, it is better to follow their lead then it is to improvise with their own ideas. As such, they are fiercely loyal and will follow them to the ends of the earth — and beyond. As the saying goes, the stupid man has no fear of death.
All of this combines into their greatest quality: unending courage. Rather than a lack of understanding of the threat they face, it is their trust that they can overcome adversity by persistence and their faith in their friends that drives them, and they will stop at nothing to help them.
Someone like that is definitely worth having in your party, even if he occasionally gaffes.