All of the below is theory and conjecture crafted by players.
Yonmarl
Yonmarl was a Fractured of Chronicle. He was brave, and not afraid to act.
Background
He was the only kin to escape Chronicle, the city damned from memory. He did so with the help of his family, but left his name behind, adopting the moniker, Yonmarl. When arrived in the Realms, he was the first to stand against giants.
The Grand Ambassador joined first. He inspired Sage Sigrid to revolt, inspired Empedocles, convinced the Mother of Kret to join, and promised The Ruby Lord all she could desire. Their rebellion against giants saw much change and the establishment of the Realms, with Unforgotten Yonmarl being named the Overking of all Realms. This story was told to us...
How did Merl know this story?
His friends led the Realm major factions, with the Grand Ambassador heading the Assembly and managing the administration of the Realms, The Ruby Lord it's justice system, Empedocles it's inventiveness, and the Mother of Kret their supply of Kretian Ant Acid.
But the Realms would not last forever, and the Overking played his part in this as well. He damned Jyggalath from memory, executed the Ruby Lord and drove the Mother of Kret to isolation. The Realms slowly succumbed to their fate with these losses, and Overking Yonmarl faded into obscurity, his fate unclear.
Why did the Overking and Empedocles want to damn Jyggalath from memory?
Discovery
Are Merl and Yonmarl the same person?
Yonmarl has been an ever present shadow over our journey of discovery. We were partways through our journey before his leadership became clear, our first hint of these Realms we visited ever being united was a single sand-worn mug in Khoving.
An item found in the depths of Namazu gave the next hint as to this mysterious Overking, and that he escaped "damnation from memory" from a place whose name we couldn't recall. There was a book in Kret's desert, a great big book that housed this secret, though we couldn't break in at the time.
Why was Bear Anything discarded in the Brine?
It was from a similar piece of trash found Namazu gut that we discovered he had a relationship with the Grand Ambassador, who served as a liaison between Yonmarl and the Realms. And he was not the only who kept a relationship with the Overking.
Merl's story after seeing the Round Crimson Pendant described six friends who were nearly inseparable and accomplished the impossible together. We have evidence to believe these friends were Yonmarl, the Grand Ambassador, Sage Sigrid, Empedocles, Mother of Kret, and The Ruby Lord.
Our suspicions of Yonmarl grew as we spoke more to Merl. At the Hall of Memory we found art of Yonmarl. They looked exactly like Merl. It's all but confirmed.
We finally made it to his home, Chronicle. We've discovered the House of the Bear, his family, deep in the crypts. There we discovered proof of his heritage.
We have told Merl the true name of Yonmarl and confirmed his origin.
Merl told us to go the village of the Assembly in Spirit, through the Crystal Caves, to find the truth of things.
Merl strongly implied the next time we come Home, our aims will be opposite and we will be unwilling enemies. We don't want this.