Six did not have a strong defined personality until "Thanks for 900,000 subscribers!". Before then, Six was shown to be somewhat vengeful after Seven kicked them out of the sub count. They are shown to have a malicious side, such as kicking Seven and agreeing to kick out Eight. In "Thanks for 900,000 subscribers!", Six appears to be somewhat irritable but also knowledgeable, as they knew that Seven's ears were squishy and that was how they were able to kick Seven. Genderless, they/them.