In Diablo 4 (D4), you enter the end game content of after you complete the campaign and there are number of end game activities to tackle and Helltide event is one of them.
As mentioned above, the Helltide event starts as soon as you reach World Tier 3 (WT3) and this is one of the most profitable activities in the game for a number of reasons, including the high XP rewards due to the large number of monsters and elite mobs, as well as the crafting materials you can only get during the Helltide events, which you need to fully upgrade and max your equipment.
However, your main focus should be on avoiding dying during Helltide related events because doing so will result in you losing most of the Aberrant Cinder you have already farmed. If you die a lot, farming will become extremely time-consuming and useless.
It is important to collect considerable amount of Aberrant Cinders quickly in order to unlock those valuable chests that would always grant you items from a specific slot.
- You need 75 Aberrant Cinders to unlock chests with rings and protective gear.
- You 125 Aberrant Cinders to unlock chests with amulets and one-handed weapons.
- You 150 Aberrant Cinders to unlock chests with two-handed weapons.
The chests in these events usually contain either legendaries or unique items, occasionally, they don't, but most of the time they do.
Then there are also some Mystery Chests called Helltide Tortured gift, they will cost you 175 Aberrant Cinders to unlock and will reward you with two to four sacred/Ancestral legendary items along with a significant quantity of Fiend Rose, Forgotten Soul and various elixirs.
You will need to do some exploration to find these chests, but it won't be too difficult.
To find these chests, you will have to explore a little bit, but nothing impossible. Each area covered by a Helltide has 1 fixed chest slot or 2 per tide, with the exception of Khejistan where there are 3 events
However, the chests location change every hour and if a chest has already been opened, then its contents are resets. It is then possible to open between 4 and 6 chests per event if you are fast enough.
Since they are so profitable, you definitely want to be the first to open them before everyone else does as they reset for everybody else once they are opened.
Now, there are a few things you should be aware of about the Mystery chests, for example mystery chests will reset on the hour that means for example if a Helltide event is running from 3:30 to 4: 30 there will be a Mystery chest reset at three o'clock. Therefore, you will have higher probability to loot more Mystery chests during that event. Like I mentioned above Mystery chests reset once they're looted so you still have to be fast.
If you want to collect those Cinders quickly, I'd recommend switching to WT3. It doesn't make any difference regarding the number of Elite and also Aberrant Cinder drop rates and of course you will be able to kill monsters much faster. So in order to be the first to unlock the Mystery chest I'd suggest switching to the lower difficulty level, defeating all those enemies and collecting the Cinders before going to the mystery chest location.