gposes 6-6-2026 (spoilers for level 90 alliance raid)
— blessings upon you, the last of us.

I got Thaleia on my alliance raid today! I haven't encountered Myths of the Realm in my roulettes for a while lately, so I was happy to re-experience it and reminisce about what the Twelve means for Jacke.
I figured I'd write something about his lore one of these days, but let me just copy what I have on his RPHub profile:
Jacke is the latest, and last, of the reincarnation of an Ancient named Hecate, one of Venat's most loyal followers. Through Hecate's fervent and fierce wish to aid and serve Venat with a more direct approach, her soul remained unsundered and she thus chose to serve as Hydaelyn's only “living” servant, akin to how the Ascians are to Zodiark.
Over time, as Hydaelyn was given Her name, this singular “agent of Her chaos” would be known as Etro - guide and shepherd, sword and shield, protector and martyr. Theirs was a singular role: protect and serve Her Chosen until their journey is fulfilled - and die, if they must, to return to the aetherial sea and be reborn anew, and the cycle repeats, over and over, for millennia, “until the rivers of time converge onto a single moment”.
Etro's domain is often in the Source, but uniquely, due to Their nature and their affinity with the afterlife, They have been known to break off some of their Soul (or their Heart, as They are wont to call it) to serve in different shards, each of them returning back to the aetherial sea to be made whole again once Their role has been fulfilled. Each “reincarnation” of Etro will remember the past lives they had lived, their mission, and the lessons they've learned with every success or failure as guidance for Their future incarnations - however, during times when They had one or multiple shards of their soul still alive, it would take a while for Their Source reincarnation to remember their duty - as was the case for Jacke.
There are very few surviving records of Etro in Hydaelyn's history as is known today. What fragments that scholars studying Their mysterious nature - including Louisoix Leveilleur - could salvage were from the First and Second Astral eras; most of everything else were destroyed or locked away following the peak of the Allagan empire, and were subsequently lost during the Fourth Umbral Calamity and the fall of Allag. Due to this, it remained a mystery to the public knowledge until today.
Something to this effect. Since Myths of the Realm dives into the true identities of the Twelve, I always thought they meant a lot to each other.