Delves are one of the new endgame activities for The War Within expansion in World of Warcraft. You don't have to get a group together to do them as Delves can be completed solo, though you will have an NPC companion to help you complete them. There are different tiers too, giving you a choice regarding difficulty levels.
You can get into Delves while you're still leveling, though you won't be able to access the higher tiers until you reach level 80. If you're ready to learn more, here's how Delves work in World of Warcraft as well as where to find them.
You can access Delves as you level, though you'll only have access to the low tiers until you reach level 80. You can do them solo with an NPC companion - Brann Bronzebeard at the start of the expansion - and he will level up and get more powerful along with you. If you have alts, Magni's progression will transfer over to them too.
Delves feel like a very loose amalgamation of Island Expeditions and Visions of N'zoth, both in feel and mechanics. They are essentially mini-dungeons with objectives that need to be completed to finish them—this may be in the form of puzzles or killing enemies and there will be specific mechanics tied to them too, such as carrying a candle to keep the darkness at bay.
There are 11 difficulty tiers and you'll need to complete the previous tier to unlock higher ones—providing you're max level. Delves will change over time too, so there will be some differences as the weeks go on. They'll also tie in with the overall story going on in the expansion and have their own seasons, complete with achievements and rewards.
Delves will also factor into World events, along with timewalking, Mythic+, and so on, offering bonuses tied to the activity while the event is active.
There are several Delves scattered across each of the new zones, and you can find them via the archway icon on your map. The maps above show the location of each.
Isle of Dorn
The Ringing Deeps
Hallowfall
Azj-Kahet
The rewards for completing Delves will vary. Though you'll generally get a mix of gear, gold, and Resonant Crystals, the latter of which is a currency that can be used to buy gear and other items from the vendors inside. You may also get a large chest at the end, which needs a key to open. These can be obtained from completing weekly activities and quests in the open world.
The gear gained from Delves isn't a replacement for raiding or taking part in Mythic+ dungeons or PvP. The item level of gear gained from taking part in this activity is capped at a heroic raiding level, at Tier 8. Anything above this tier won't gain better gear rewards. You'll also get the chance to get additional gear from the Great Vault—in addition to raids and dungeons, Delve completion will also fill up a row, giving you an extra piece of loot at after the weekly reset.
Seasonal rewards will also available, including transmog sets, toys and mounts.
