The power of water is its ability to take any shape, those are Rhodeia's favourite words and a statement of confidence in her own power as a lochfolk. Water is the mother of all life, and what was borne from water will eventually return to the water like a drop into the vast sea. As such, water is the greatest and most encompassing element in the whole of Teyvat.
Or at least, those were what the original Hydro Archon told him when she was still around.
Water is the connection between them both. Water was the catalyst that contributed to their very first meeting, water was the power which she bestowed upon him and taught him to wield, water was his every end and beginning, reborn again and again for hundreds and thousands of years as they watched over their nation together, the Nation of Justice.
They never did manage to solve the mystery that is his existence. They never did understand how and why he came to be other than knowing that he is a Descender. They never knew why he would die by dissolving into water only to be reborn anew from water. All they knew was that things happened as it is and they had long since accepted it as a fact that they will never comprehend.
The memories from before he descended into this world had long since eroded. He could barely recall anything by the time he spent two hundred years in this world. He eventually became one with Teyvat and he knew Teyvat accepted him when he saw his own stars manifesting in the false sky. His constellations shone and the stars that represented his existence promised him that his story will never end. In a manner of speaking, he possesses a power even greater than the archons.
"What's wrong, my Grand Duelist? Feeling sentimental today?"
The cataclysm broke out and he followed after his archon to the Tunigi Hollow to combat the forces of the Abyss. He died protecting his archon and when he woke up again it was already 500 years into the future. So many had changed, so many things had happened, his archon had been dead for more than five centuries.
The Grand Duelist of Fontaine failed in his job. He did not succeed in protecting his archon.
"Descender from another world? Cooooool! Hah, now I finally have something that the other archons don't! Hey, how about you become my sword?"
They found each other shortly after she was crowned as the Hydro Archon. She was very approachable despite being a literal god. She has her own immaturities and flaws, proving that even the divine are not perfect beings. She's pompous, dramatic, picky and infuriatingly problematic but that is the original Hydro Archon that emerged as the ultimate victor in the Archon War and subsequently unified Fontaine.
"Everyone is equal in the face of justice, even Gods. If the people so wish they could even pass judgement unto me, assuming that they are in the right and I am indeed, in the wrong."
The Hydro Archon presides over the domain of "justice" but it's not possible for her to oversee every single trial, big or small, when she has so many matters to see to as a deity of a nation. She established the Court of Fontaine which subsequently saw to the creation of the Opera Epiclese, she created the Oratrice Mecanique d'Analyse Cardinale to ensure that the laws in her nation are fair and just so that punishment will be meted out to evildoers and protect the innocent. He bore witness to every deed she made to build Fontaine into what it is and assisted her to make her vision a reality.
She bestowed upon him the longsword created from a very special ore that can only be found in the deepest depths of the purest of water. The sword will later be known as the Sword of Temporal Justice, a symbol and icon of the will of the Hydro Archon wielded by her chosen vassal, the Grand Duelist of Fontaine, Lucine Fontinas. By her will he had used this same sword to slay Fontaine's enemies, protect her people and her ideals, partake in duels in the name of justice, and also stopped countless enemies that dared to seek their archon harm.
But the Grand Duelist wasn't strong enough. He wasn't able to prevent his archon from perishing during the cataclysm.
The cold sensation of water dripping onto his skin pulled him back to reality. He looked up, spotting the dark grey clouds gathering overhead and the small drizzle turned into a downpour in a matter of seconds.
It's been a week since he woke up and found himself 500 years into the future and the only thing that seemed to remain the same is the gloomy atmosphere permeating the city whenever it rains.
"It's raining again."
"Do you need me to get you a parasol?"
"Can't you just stop the rain?"
"Why would I? Rain is my way of blessing my people."
His view of the pouring rain was suddenly obscured by a parasol that had definitely seen better days. He looked back, spotting the girl and her twin brother looking at him with a concerned look on their faces. They are the children who he had saved just two days ago.
"L-Lucian, it's raining."
The rain wouldn't hurt him nor will he ever get sick from the rain. He had long since ceased being human and is closer in biological makeup to a hydro elemental being, but he appreciates their act of kindness nonetheless.
"Let's go."
The three of them walked down the streets of Fontaine sharing a single parasol. He had a lot to think about these past seven days. With the passing of the archon whom he had served for thousands of years he suddenly found himself living without a purpose in mind. It's been five hundred years, Fontaine had already moved on from the loss of their original archon and Grand Duelist.
Strictly speaking, Fontaine no longer needs him. They hadn't needed him since five hundred years ago and are thriving despite his absence. They hadn't needed their Grand Duelist and his sword.
So what should he do now? What should he live for?
If only you are here to hear my voice, my archon.
What is my purpose now that you are gone?