I did say I would post more oc stuff so here’s some old sketches of Ahab; the first and second time he saw other kuo toa. Ahab was raised by humans, and never came close enough to speak to another of his own kind until his 20’s. Their communities are small and remote, and after centuries of conflict and persecution by the land races they tend to avoid contact with all outsiders.
There are multiple reasons kuo toa seldom integrate in land race societies, and a lot of them have to do with lack of accommodation for their amphibious bodies. Their skin needs to be at least slightly damp at all times or they experience severe discomfort, and Ahab is prone to scale shedding and skin infections where clothes chafe away his mucus layer. Kuo toa are also nocturnal, with eyes that see poorly in bright light, and do not tolerate warm environments well. Ahab really only survived because he grew up on a ship, and after learning to speak common found use as go-to nightwatchman and hull scraper (he often eats the barnacles and other foulers to supplement ship rations, much of which he doesn’t digest well).