Phlegethon is a river of fire and/or lava in Greek mythology. Located in the Underworld, it flows alongside the river Styx but leads directly into Tartarus, the prison of the Titans and other enemies of the Olympians.
The river is also featured in The Divine Comedy, where it is described as a river of boiling blood located in the Seventh Circle of Hell (Violence). Here, Phlegethon is used as a punishment for those who commited violence against other people, such as murderers and warmongers.
Why should we change Acheron’s name to Phlegethon?
Sounds cool (IMO)
More unique than the name “Acheron,” which is already used by other, more popular characters
In lore, someone named after a literal river of fire that leads directly into hell sounds pretty intimidating and dangerous, fitting for someone like Durza (who, you know, can steal Curses and has destroyed the world).
Gives the opportunity for a character (likely one of the Peacekeeper’s allies) to call the Dark Wizard, “Phlegm-athon” as an insult
Other name suggestions (feel free to comment some of your own!)
Phlegethon, afaik, is not just a river of fire, but also, (according to Riordian) a river of healing. Neither of which the antagonist formerly known as Durza has a major connection to. C- for effort.