Advespas appeared as giant wasps roughly the size of bears. While their heads featured dripping mandibles and antenna-like horns, they also had the face of a deformed woman. A barbed, stinger was located at the end of their lower abdomens, which could be raised above their heads like the tail of a scorpion. Most advespas were entirely black, with a chitinous exoskeleton and insectoid wings as dark as obsidian. Some smaller advespas however, possessed horizontal markings of yellow, orange or red on their abdomens.
Like most devils advespas were cruel creatures with a strong sense of order. They held a strong sense of discipline and were able to easily cooperate with one another.
Acid or holy power was required to harm an advespa without it regenerating. They could summon a couple more advespas once a day with a variable rate of success. Three times a day, an advespa could cast at will change self, command, produce flame and pyrotechnics.
Advespas normally used aerial assaults, grasping their enemies with their raking claws before repeatedly plunging their stingers into their foes. Their poison quickly sapped the enemy's strength until the helpless victim was carried off into the sky. 
Advespas were ranked by the amount of additional markings on their abdomens. Those with more colored markings were of higher station and usually the commanders of patrolling squads and swarms. They were normally in service to more powerful baatezu like the amnizus, capturing intruders of their domains.
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Ed Bonny, Jeff Grubb, Rich Redman, Skip Williams, and Steve Winter (September 2002). Monster Manual II 3rd edition. (TSR, Inc), pp. 67–69. ISBN 07-8692-873-5.
- ↑ 2.0 2.1 2.2 Eric Cagle. Know Your Enemy (Part 16) (Web). Archived from the original on 2007-01-04. Retrieved on 2009-03-30.
- ↑ 3.0 3.1 3.2 Richard Lee Byers (March 2008). Undead. (Wizards of the Coast), pp. 233, 234. ISBN 978-0-7869-4783-6.
Least: Advespa • Lemure • Merregon • Nupperibo
Lesser: Abishai (Black • Blue • Green • Red • White) • Barbazu • Hamatula • Narzugon • Osyluth • Spinagon
Greater: Amnizu • Cornugon • Erinyes • Gelugon • Paeliryon • Pit fiend • War devil
Alu-fiend • Archdevil • Cambion • Fimbrul devil • Hellcat • Imp • Kyton • Seared devil • Succubus • Tar devil