The Pure One is a title granted to both Thomas Covenant and Saltheart Foamfollower by miscellaneous mud mongrels and the Lurker’s little lickspittles. Refrain from adding an accent to the letter e (é) in the word "pure", or you may end up with something utterly unrelated.
For his part, Foamy fulfilled a prophecy of the Jheherrin after some rounds of swimming in the Dark Lord’s lavapool, as a consequence of which every deep-rooted regret and fault melted away, and the reborn Giant could laugh said evil entity into temporary oblivion. This operation apparently redeemed the clay critters, even if it does sound a teensy bit like a direct-to-video Disney sequel.
The Feroce name Covenant thus in the Third Chronicles: the wielder of “abhorrent metal” and other eldritch powers that impressed both the Swamp Thing and its toadies. He denied such glorifications, yet perhaps became one in the end after slicing away a Raver-infested tentacle and therefore playing a crucial part in saving the Lurker’s existence, and by rebuilding time and space from worm-gnawed scraps with wild magic.