Rob2628 provides a comprehensive guide to farming Infernal Hordes in Diablo 4 Season 10, focusing on how to maximize chaos uniques and ether. A rare chance to get 12-13 chaos uniques in one run and how to achieve up to 4,000+ cinders/ether per run. Note that there was a patch on Oct. 07 which helps the soul spires so they could be higher on the list now.
Chaos Waves - These can spawn goblins and, specifically, Ether Lords, which are powerful bosses that drop significant amounts of ether
S Tier
Aether Lords 3x - This significantly multiplies the ether dropped by Ether Lords
Aether Lords +5
Aether Fiends are Lords / +2 - Combining this with the previous boon means Ether Fiends, which spawn from Etheric Masses, become Ether Lords, leading to huge ether gains
Masses Spawn Fiends
Souls Spires - These can be very strong, especially with combinations that increase ether drops within their range
A Tier
Faster Event Spawns (if early waves) - Killing monsters spawns ether events 50% faster, which is consistently strong
Stalking Devil (Demon) +100 - This boss gives 100 ether. It’s more beneficial in later waves (like the last wave) but less so in early waves.