Internet/young-people slang. The letter 'E' is read as the English letter ('ee'), so 'E
人' is read 'ee rén'. Pair: I
人 (yī-rén) — introvert. Spawned compounds like
装E (zhuāng E, 'pretending to be extroverted') and
显I (xiǎn I, 'revealing your introverted side').