Bill Cipher

Bill Cipher is a triangular dream demon who serves as the main antagonist in Gravity Falls, although, he does not have a major role in the spotlight until Season 2, especially in the second half of that season.

Origin
Bill Cipher is based off the Eye of Providence, a symbol that represents the all-seeing eye of God, as well as a secret society many people call "The Illuminati". Appropriately enough, Bill has the ability to foresee the future, along with keeping an eye on many real-life events.

Bill was originally going to be green, but was changed to yellow, since he looked more like a leaf. Bill had many names beforehand, but many of them got rejected. One night, when Alex Hirsch was coming up with ciphers for Season 1, he decided that Bill's second name was going to be Cipher, hence the show's tendency to scatter cryptic and coded messages throughout each episode and short.

In the 2015 Bill Cipher AMA on Reddit, along with the series finale; Weirdmageddon 3: Take Back the Falls, Bill Cipher originally hails from a dimension that is very similar to Flatland, a novel by Edwin Abbott Abbot that focuses on a society of shapes, and their position that's judged by the amounts of sides that they have.

Reception
When Bill Cipher was formally introduced in Dreamscaperers, he became an instant fan favourite, for his affable, albeit, obnoxious attitude. Many fans also enjoy his sociopathic tendencies, such as pulling out deer teeth to terrify Gideon.

Many people praise him as one of Disney's best villains after his true motives were revealed over time. Many fans fell in love with his possession of Dipper Pines in Sock Opera, who is appropriately dubbed by many, as well as Mabel Pines, as "Bipper". Bill is also praised by his fans for his warped sense of humour, as well as being a smart, calculative, and formidable villain the show had ever established.

Counterparts
Aku (Samurai Jack) Dimentio (Super Paper Mario) Flowey the Flower (Undertale) Him (The PowerPuff Girls) Hades (Hercules) Dr. Facilier (The Princess & The Frog)