Stephen Colbert leaves Comedy Central's satirical political talk show "The Colbert Report" after nine years Thursday night. He will become host of the "Late Show" on CBS, replacing David Letterman in May. So ends the "Stephen Colbert" character he created: the outlandishly tongue-in-cheek conservative host who leapt from late-night TV to become a political and pop culture phenomenon. Many of his "Colbert Nation" fans are left trying to imagine life without his incessant lampooning of the Washington establishment and TV pundits. Here's a brief explanation of Stephen Colbert and the alter ego he is retiring:

A SATIRICAL SPIN-OFF:

The actor and comedian first created his Colbert character in 1997 as a correspondent for Comedy Central's "The Daily Show." The persona, described by the real Colbert as "self-important, poorly informed, well-intentioned but an idiot," got his own show in 2005. Largely inspired by conservative Bill O'Reilly, the Fox News pundit, the satirical, fact-challenged "Stephen Colbert" preached the opposite of what the real-life Colbert meant to say, a long-running joke that never ran its course. The underlying theme was a forceful poke at bombastic nationalism as discontent over the Iraq War was surging. "The Colbert Report" won four Emmys and two Peabody awards.

COLBERT FOR PRESIDENT?!

In the first episode, Colbert coined the term "truthiness," defining it as "truth that comes from the gut, not books." The American Dialect Society and Merriam-Webster named "truthiness" the word of the year. As Colbert's character gained popularity, he escaped the confines of cable TV. He famously skewered President George W. Bush at the White House Correspondents' dinner in 2006, mocking his handling of Iraq and Hurricane Katrina. He attempted to run for president in 2008, testified before a congressional committee on immigration reform and raised real money in an award-winning parody of loosened political fundraising laws with his Super Political Action Committee, "Americans for a Better Tomorrow, Tomorrow." A study published this year by the Annenberg Public Policy Center found Colbert had more success explaining complex fundraising rules than traditional media.