Ah, Ashen One. I see you have returned for the final piece of this Lore Theory… It has all been leading up to this. If you want to go back and see how we got to this point, here are <
with a few added details…
Yes, I believe the dragonslayer to be none other than Solaire.
"Woah there, that's insane! How is Solaire a dragonslayer?! Nothing points to that at all!"
Well, now that yo-
"Yeah he's right! And isn't Solaire from Astora, not Heide?"
Yes, but you se-
"Yeah, isn't Solaire just an Undead?"
"He doesn't use a Greatshield at all!"
"Yeah, Havel works much better! He is a Dragonslayer afterall!"
"Isn't Solaire the Furtive Pygmy?"
"No, he's the Carthus Sandworm!"
"I thought he was the Firstborn…?"
"No, he's Velka obviously."
Okay, okay, let's slow down a bit!
Firstly, we all know that the Nameless King is the Firstborn, and there are no connections to the Furtive Pygmy, or (sadly) Velka.
And yes, there is still room for the Carthus Sandworm theory; I'll get to that.
Now, the truly glaring opposition is that Solaire is not a Dragonslayer. However, he wields Lightning Spear, a spell specifically crafted to pierce dragon scales. Also, we find him standing with his back to the bridge, guarded by the Hellkite Drake. Brave, and with the tools to hunt dragons; it fits, no?
As for why he would use a smaller shield and weapon than the Dragonslayer Armour, his armor states that it was handmade, and (guess what!) made of iron, just like the Heide Mask and the Dragonslayer Armour! Besides, if you were in search of your Sun, would you walk around in a big suit of armor? Your friends might lock you up in a tower cause they thought you went crazy!
Hahaha, rock solid joke, right?~ Cough, cough, sorry.
Also on the subject of his armor, the similarities are there with the Heide Knight armors, and we already have seen the connections between Ornstein and Heide. It may be possible that he traveled to Heide, hearing of a Dragonslaying knight resembling Ornstein, and his heroics inspired the knights to adopt his armor; or, in need of armor, he scrapped together some spare pieces they had and made his own set.
Now that I have addressed some of the cons, let's look at some supporting evidence.
In Dark Souls 3, we can trade certain items for Solaire's armor. The first two, namely the Homeward Bone and Seed of the Giant Tree, are fairly general; of note however, is the use of the Seed in the same game that Children of the Sun can now invade. However, the next item is Siegbrau, which is an Undead drink for long distances, which supports the idea that Solaire has been journeying far to search for the Firstborn, after all, he became Undead just to make the pilgrimage just so he could find "his Sun". Then we trade a Lightning Urn; the description reads:
"Dragon-hunting tool used by Lothric knights. Explodes upon contact, inflicting lightning damage.
The knights of Lothric have since tamed dragons, but were once hunters of dragons themselves.
This explains their special hunting gear, and why they worshipped the sun."
Not only is this a dragonhunting item, but it also has links to Lothric knights, adherents to the Children of Sunlight as evidenced by the Altar that is, incidentally, right before the Dragonslayer Armour boss fight! If that wasnt enough, the final item, which we trade for his shield, just so happens to be the Mendicant's Staff, which we find in none other than Archdragon Peak. While we cannot say for sure why trading these items with a baby crow gives us his armor, the link grows even stronger when we consider this.
The biggest piece of evidence, however, lies in his Sunlight Straight Sword. Not only is it infusable, allowing for Lightning Blade (and also being described as being infused with Lightning!), but it's Weapon Art is Oath of Sunlight, which is a tale of one sided adoration and almost an exact replica of the spell Sacred Oath!
Add to this that the similarity between it and the straight swords featured in the Sacred Oath spell, Lightning Blade spell, and the sword held by the baby near DS1's Sunlight Altar, and we begin to see a pattern; is it possible that the blade is an heirloom, which Solaire took up in order to remind the Firstborn of his duty to Lordran and his people? I admit that it is still possible for him to merely be a Nameless King fanboy, but the evidence is compounding.
It is also worth noting that Gwyn and his Silver Knights descended into the realm of Demons to combat the Bed of Chaos, and that this is the only Lord Soul area where we can summon Solaire. And just like Gwyn and his Black Knights, this is where we see Solaire descend into darkness… Unless we save him, wherein he helps us one final time, defeating Gwyn with the Chosen Undead and Linking the Flame in his world.
Or, you know, being possessed by the sunlight Maggot and becoming the Carthus Sandworm. I mean, it does drop Lightning Stake, yet another miracle used to hunt dragons.
Regardless, this all links up in that Solaire becomes possessed by the Sunlight maggot, while the Dragonslayer Armour becomes possessed by the Pilgrim Butterflies. If Solaire truly is the Dragonslayer, this little detail is so perfect.
So, alas, we have come to our conclusion. It might not be a definite fact that Solaire is the Dragonslayer, but hopefully I gave you all some good information to chew over and make you own decisions!
For me, the story of three brave Dragonslayers, who leave it all behind to save Dragons, find their old friend, and to finish the Lord of Sunlight's wish, just feels right to me. Each of these characters has so much rich lore connected to them, and are indeed some of my favorites.
Thank you so much for reading through this all, fellow Undead! I look forward to your comments, and as always, Praise the Sun!