The nupperibo (least devil) first appeared in the first edition Monster Manual II (1983).
The nupperibo least baatezu appear in second edition in the Monstrous Compendium Volume Outer Planes Appendix (1991) under the "baatezu" heading, and is also detailed under the "baatezu" heading in the first Planescape Monstrous Compendium Appendix (1994).
In Baatezu hierarchy only one step higher off lemures. (In 1st edition AD&D, they were one step below lemures.) They are mindless bulks, harmed permanently only by good-aligned magic and holy weapons. These creatures are the natural spawn of Baator and not considered true Baatezu, so other higher ranking devils will usually destroy these and re-mold them into Lemures. This causes many Baatezu uneasiness as an even more ancient race is native to their home plane. Fortunately for the Baatezu, almost no Nupperibos survive long enough to transform into anything greater. Note that in the most recent book, Fiendish Codex II: Tyrants of the Nine Hells, the origin of the Nupperibo was changed. Currently they are true Baatezu that have been demoted in station and form by their superiors. Meaning due to the odd bureaucracy of hell, the nupperibo is the next "promotion" of form coming after and selected from the ranks of the lemure, but is in technical rank a demotion below it, and serves lemures as their fodder. This is the only time in the delineation of the hierarchy this has canonically occurred, likely to explain the discrepancy from 1st edition onward.
- Gygax, Gary. Monster Manual II (TSR, 1983)
- LaFountain, J. Paul. Monstrous Compendium Outer Planes Appendix. (TSR, 1991)
- Varney, Allen, ed. Planescape Monstrous Compendium Appendix (TSR, 1994)
- Laws, Robin D., and Robert J. Schwalb. Fiendish Codex II: Tyrants of the Nine Hells (Wizards of the Coast, 2006)
- Green, Scott; Peterson, Clark (2002). Tome of Horrors. Necromancer Games. pp. 102–103. ISBN 1-58846-112-2.