A self-described "self-taught human," a slime of unknown origin that became fascinated by humans and fully committed to being one. The fact that he isn't really one is a bit of an insecurity of his.
Dex is intelligent, rational, remarkably well-read, and has great attention to detail. More often than not, it’s his quick and clever thinking that gets him and Hydra out of the many precarious situations they find themselves in. Despite this, he’s self-conscious and lacks confidence. He takes almost everything too seriously and has a bad habit of overthinking. So when he makes a mistake or something doesn’t go according to his plans, he has a hard time keeping it together (literally).
Above all else, Dex longs to be taken seriously and to be seen by others as a mature and respectable person. In order to accomplish this, he tries his hardest to fake an aura of confidence and employs a bit of a cocky and condescending attitude towards strangers, making cynical or sarcastic remarks often, but the majority of people can see right through him (also literally).