The Corps of Ringbearers are a recurring shared world fanfiction concept, created by Brother Grimace. They are a force that travel the multiverse fighting supernatural threats, wielding alchemical Defender Rings and backed up by heavy artillery such as Sky Vaults. Command rests with the Ringmasters, and key comms infrastructure includes Beacon Terra One.
In March of 2008, after reading a number of zombie fiction (including such works as Doggieboy's A Little Vacation and The Zombie Survival Guide), Brother Grimace created the concept of the Defender Rings and the Ringbearers - individuals in the vein of the Green Lantern Corps and Rom. Corp backstory has that the original Ringbearers formed their Defender Rings to battle a zombie outbreak, akin to the Spaceknights forming to fight the Dire Wraiths.
Ringbearers went on to appear in numerous fanfics by Grimace, Doggieboy, Richard Lobinske, and others, in particular Grimace's "Tales of the Ringbearers" vignettes. Among their ranks include alternate versions of fanfic characters like Martin Peters and Danielle Todds as well as alternate canon figures (and newly written characters).
They were a key part in the 2010s mega-crossover "Judith Strikes"/"Worldburner"/"Worldhopper" as they suffered horrific losses in the attempt to slow down Judith. After the loss of their home universe, they initiated Code Kerensky, a withdrawal from the multiverse that one of their Amelia's forgot to rendezvous for - revealed to be a trick as the entire Corps warped out her Ring into the "101" universe to flatten Judith's army. The threat over, the group regrouped and rebuilt.
A large amount of background information about the Ringbearers was on this very wiki but was lost during the Crash Of 2016.