Ashava, The Pestilent: Since this boss was in the beta and you literally have to fight her during the campaign D2R Items, I'm sure you're all very familiar. If not, you need to watch out for her arcing claw attacks, jumps, and poison breath.

Whoever you fight, you've got a chance at getting some Legendary gear and, if you're facing them on Nightmare world level, even Unique items.

Diablo 4 Helltides are events that happen randomly across Sanctuary when you set the game to Nightmare World Tier difficulty or higher. These pop up every few hours and you can kill enemies and collect currency to exchange for gear and other goodies. Helltides are also the best place to look for Fiend Roses. If you're ready to learn more about these potentially lucrative events, here's everything you need to know about Diablo 4 Helltides.

Diablo 4 Helltides: How to unlock the event
First up, to even see Helltides on the map, you need to make sure you've switched the World Tier to Nightmare. To unlock anything beyond Veteran, you must finish the main campaign and complete the Priority quest that sends you to your first capstone dungeon, Cathedral of Light cheap D2R ladder items. You'll need to be around level 50 to complete it and, depending on your class, it can be pretty tough.