Randall Flagg has been featured in The Stand and Dark Tower.
Randall Flagg . He has a variety of names , usually with the initial letters `` R. F. '' but with occasional exceptions , such as Walter o'Dim ( originally envisioned by King as a separate character ) in The Dark Tower series . Flagg first appeared in The Stand as a demonic figure who wreaks havoc after a plague kills most of the population . Flagg was a primary antagonist in King 's epic series , The Dark Tower , who tries to keep protagonist Roland Deschain from reaching the Tower ( the linchpin of existence ) so he can claim it for himself and become a god .