The Pill comics are a series of webcomics created by 4chan's /x/ board. They feature the pill characters, supposedly humorous personifications of the metaphysical paths the pills represent, but in reality they represent the various strains of
shitposters found on /x/. For example, the main character Green Pill represents the satirically ideal New Age conspiracy theorist. The Green Pill character has also become a secondary mascot for /x/ with /x/-tan.
The webcomics are all made by anonymous contributors, mostly never by the same person.
- Green Pill is the main character, and a caricature of the "ideal" /x/ poster, obsessed with alternative philosophies and government conspiracies. He is a gnostic who fights against the Illuminati and the reptilians on Earth and in the astral realms.
- Red Pill is a neo-nazi who believes the Jews are behind everything, and a parody for the various /pol/ vagrants found on /x/ and 4chan in general.
- Blue Pill is an indoctrinated by the Illuminati and holds simplistic world views. He (or she, depending on the comic) represents /x/'s bugbears, and so can simultaneously represent skeptics, ultra-liberal/feminist "social justice warriors" or just the masses in general.
- Indigo Pill is the arch-nemesis of Green Pill. He is part of the Illuminati and an ally of the reptilians. Could be a mockery of the more try-hard /x/ users who want to be vampires or contact demons or whatever.
- Brown Pill is mostly neutral about the Illuminati, but he helps Green Pill defend the world against the Demiurge. What all /x/ users wish they were.
- White Pill a discordian who doesn't care about the Illuminati, nor about anything else than himself. A parody of the rejects who drift out of /b/ and/or [s4s] and regularly shitpost in discussions.
- Iron Pill is tribal savage Eurotrash and proud of it and so fights against the degeneracy. How the more pretentious /pol/ users like to see themselves. 
The comics quickly spread to the /pol/ and /fit/ boards, which created the Iron Pill character in response (because Redpill being a podgy autistic manlet struck too close to home for some). Eventually, the green pill concept spread to other boards, such as /lit/.
Green Pill appears almost exclusively on 4chan.