For nine years, Stephen Colbert has relentlessly maintained his pompous, deeply ridiculous but consistently appealing conservative blowhard character on his late-night show, "The Colbert Report" — so much so that when he puts the character to rest for good on Thursday night, he may have to resort to comicide. The Grim Reaper is his last guest.

Devoted fans of "The Colbert Report" (the final T is silent) have dreaded this day since April 10, when their favorite late-night star announced that he was leaving to become the successor to David Letterman on CBS.

Mr. Colbert has steered clear of commenting on his plans for the last show, other than on-air comments that the end is near. But whatever comic exercise Mr. Colbert devises to end his multi-award-winning run on Comedy Central, including perhaps some symbolic hara-kiri for the character he brought into American homes four nights a week, he has left an indelible mark on late-night television comedy.

And he did it in a way almost no one thought was possible, or sustainable: as a fake host, a fictional character using Mr. Colbert's own name who was an elaborate parody of a bloviating political talk show host.