THIS GUIDE WILL NOT BE UPDATED FOR MIDNIGHT, ALL INFORMATION PROVIDED MAY BE IRRELEVANT OR INCORRECT.
Due to negligence during The War Within, the achievement Herald of the Titans was more difficult to obtain, as the item levels obtainable by a level 30 were higher than the requirement to actually qualify for the achievement. Since the negligence has continued to Midnight, the item level requirement is now considerably generous, and you do not need to spend copious amounts of effort farming gear at weird levels. Here's how you can get this achievement.
This part should be self-explanatory. You level a character to level 30....HOWEVER, I suggest using an agility-based tank class for this!
This includes Vengeance Demon Hunter, Guardian Druid, and Brewmaster Monk. This will make the later steps slightly easier.
Also, turn off your experience. This is explained here if you don't know how to do that for some reason.
Since the item level requirement is still ilvl107, and the typical gear that drops for a level 30 is now between ilvl30-ilvl47. Here's what I suggest...
A. There are ilvl65 greens usable by level 30s on the auction house. Use those.
B. Farm gear from late TBC or early WOTLK raids by having a high level carry.
C. Buy ilvl47 socketed gear from pvp vendors using Marks of Honor.
DO NOT USE HEIRLOOMS.
The mechanics for how this trinket works is explained on my trinkets page, but the agreed consensus is that it stems from spaghetti code involving how Present Time and Shadowlands dungeons operate. We will likely never get confirmation about this, and the fix is likely enough of a pain in the ass that they haven't bothered with it yet. This step is required!!!!!!
Anyway, you need have your loot spec set to an Agility DPS spec for it to drop. If you ignored my advice on class, you might need to have it traded.
Self-explanatory. Here's my suggestions:
A. I've seen stamina gems recommended. I don't know if it would hurt or not but your game plan is to stay alive as long as possible, sooo....
B. Shadowlands gems. You will need a LOT of them, but the revitalizing gem is still really good. Please refer to this. The healing gem's healing wasn't changed.
C. I would go based off your class's suggested stat priority, but crit and mastery are probably fair bets - crit for the trinket, mastery for defensive purposes.
You will need to be in Present Time in order to enter raids. The game won't let you otherwise, and the ooze trinket is only overpowered in Present Time.
Do one of two methods to obtain a lockout:
Option A: Go into Ulduar and get the first two bosses killed (Flame Leviathan and XT-002 Deconstructor). Other bosses are optional, which is directly mentioned by the NPCs in the roleplay dialogue, and Algalon has been free to enter without a full clear for a while. You might have difficulty with this solo.
Option B: Have a max level character in a solo group kill Flame Leviathan, XT, and Kologarn, then that character will need to leave the raid, reset instance, and form a group outside the instance with the level 30(s). The level 30(s) will then enter the instance and do their thing, and when the group confirms the lockout is working correctly (the shield will be down), they can take the teleporter and the max level can leave the raid group.
Go to Algalon. You take a right after the antechamber entrance, opposite direction of Iron Council.
Start the RP. Algalon won't engage you until you hit him.
Stay alive as long as humanly possible until your Infinitely Divisible Ooze procs. Your trinket should be able to chunk down the boss rapidly.
Boss dies, and the achievement is rewarded. You no longer have to think about this title or achievement.
Okay. There are groups who run Herald as a whole raid group. You can find some of these groups at the bottom here.
There's a lot of guessing on why sometimes it doesn't show up, and some guesses make less sense than other guesses. All of this speculation will never truly be resolved because that would require Blizzard to make statements about a neglected fifteen year old achievement.
If you used a max level to clear the raid, have everyone in the instance leave, and have that character reset instance to get the skip again. Or, if you didn't, you'll do the same thing except with no skips. You will be allowed to raid again, just with no loot drops.
Not my problem lol