Shemeska
Adventurer
Succubi detached from devils can now breed and it appears to be the primary was they reproduce vs. evil souls like most other fiends, so that's a big difference because it frees them more from the lower planes then other fiends.
Dispite not being the most powerful fiends, the breeding means they can invade any realms and grow in numbers in time, which in one way makes them the scarest of fiends who depend more on damned souls to build thier numbers up.
Demons and yugoloths (with lots of specifics for lesser versus greater 'loths) could breed amongst their own kind in 2e and 3e. With some exceptions that varied by edition, only unique devils could procreate. Succubi being able to breed would be a direct continuation of the 2e/3e lore on demons, and not a major difference between them and most other fiend types.