Born a later generation of archdragon, Midir had the most peculiar upbringing for his kind. Rather than be hunted like the rest, he was raised by the gods of Anor Londo, which explains why he bears name of Celtic origin like so many of them. And not just any of those gods either. Old Moonlight is a peculiar spell to transpose from Midir’s soul. The sorcery gives form to a memory of an old sword found in the Darkeater’s depths through souls, which reveals a lot about the dragon. “Depths” (深層) can be used in terms of the psyche, so the sword isn’t deep within his body but his mind. Weapons and spells derived from souls either embody the inherent nature of the soul or reflect the memories or experiences they contain. And taking into account the concept of depth psychology, (深層心理学) this sword is most likely an abstraction of Midir’s subconscious memory. This makes Old Moonlight a perfect complement to the Frayed Blade, which embodies Midir’s physical state. Moreover, this abstraction probably denotes personal experience with Seath.

The sorcery’s description acknowledges that it shares the name “moonlight” with the greatsword associated with the white dragon due to being in some way derived from him. However, it also notes that the blade’s form is slightly different from that of the Moonlight Greatsword, closer to the beginning. That last point is an obvious reference to the old sword’s design, which strongly resembles the Moonlight Sword acquired in King’s Field, a series of games developed by FromSoftware before Dark Souls and even its spiritual predecessor Demon’s Souls. But it goes beyond just a meta reference. The term for “beginning” (はじまり) is the same term used to describe the beginning of the Age of Fire as portrayed in the opening cinematic for the original Dark Souls, (DS1) the period where Seath betrays his brethren during the dragon hunts. And considering that this memory of Seath is so deep in his subconscious, Midir was likely very young at the time. In that case, his memory manifesting Seath’s moonlight may be due to personal experience with the paledrake’s sorcery following the latter’s betrayal during his formative years.

Sorcery that forms a memory of an old sword which was in Midir’s depths with souls and attacks with it.

Attacks are accompanied by light waves, and their might and power are increased by continuing the stance before the attack.

The name of the old sword, this too is moonlight, but it has a slightly different appearance than that of the white dragon Seath. That memory seems to be closer to the beginning.

Whatever the case, Midir was ultimately spared the envious dragon’s wrath and instead taken in to be raised at Anor Londo. While DS1 did imply that the gods had reared dragons, including archdragons, it is still odd for Seath to have taken such action. Would he have really taken pity on the innocent pup of the brethren he hated? Would he truly just take in a child on a whim, especially with what the future Duke had to look forward to? No, neither scenario explains Seath’s rationale. It is more likely that the tireless researcher saw the benefits of keeping Midir close. Recall the paledrake’s obsession with acquiring his kind’s immortal scales. With his early inquiries focusing on understanding petrification, having a living stone-hide specimen to comparatively study would be beneficial — cut content likewise reveals plans to have the boss wield his later crystals as a weapon. Therefore, practicality superseded personal animosity, and the sorcerer god adopted the young archdragon for research; fitting that he named him Midir, the son of a god associated with fatherliness, magic, and wisdom in Celtic mythology.

Thanks to Seath bringing him under his wing, Midir naturally grew up alongside Shira, who considers the archdragon to be a dear friend. Whether these childhood friends acted as siblings or as master and servant, her unique parentage ensured that the Duke’s daughter could relate to Midir where the other medials could not. And no matter how they spent their younger years together, both ultimately stayed as a pair even as they left the royal capital. Shira notes that Midir has “returned” to the Ringed City, implying that he had been originally stationed there just like her. Indeed, we obtain the rusted crest ornament for Filianore’s crest by killing the archdragon, suggesting that he too is a Spear of the Church. And as a spear, he was assigned an important duty whilst the princess entered her long sleep: devouring the Dark. With his great power and immortal body, the dragon was well suited to hunting the Abyss until the gods had successfully driven out the Dark for good. And so, to protect his charge’s sleep, Midir agreed to this pact and set out into the world.

Considering his absence from where the Abyss manifested in past games, the Darkeater had in all likelihood been flying around blindly until he spotted signs of the Dark. He would then proceed to use his claws, jaws, and fiery breath to tear, gulp down, and sear the Abyss. It is certainly an inefficient system, but it was the most that the Church of Filianore could do in their position. Nonetheless, it is no surprise that such close contact with the Abyss resulted in it eventually afflicting the dragon. As reflected in the frayed katana derived from his soul, Midir’s body has been slowly twisted and degraded by abyssal corruption, the Dark crystallizing upon his stone scales; his mind has been faring no better. Yet much like Artorias, he persisted in his duty, devouring the Dark wherever he encountered it.

And then, the afflicted dragon returned to the Ringed City, most likely having been recalled by the Church of Filianore. Shira indicates that his homecoming is in accordance with his pact to protect Filianore’s sleep, and we do only see Midir attack us as we attempt to approach her church from the Shared Grave. With the Abyss now creeping upon the church’s foundation, the Darkeater was certainly needed. And as bearer of Filianore’s crest, the archdragon would undoubtedly hear the summons of Argo or any of the other ranking church members — whether someone of his size could actually be instantly warped back with that magic is another story. Regardless of how, Midir ultimately did make it back, but by then, it was already too late.

Perhaps you have already seen it, but there is a lone dragon in this city. A descendant of the old dragons, Midir. That dragon who eats the Dark was for that reason afflicted by it, and in the end returned to this city. For the sake of protecting the princess’ sleep in accordance with the old pact.

The Dark accompanies the dragon’s flames with every breath, and he can rouse the humanity from the corpses laying around his boss room to assault us. The Dark is already affecting him to the core, causing this proud servant of the gods to degenerate into a feral beast. He is apparently only still fulfilling his duty on instinct from what little of his memory remains. And hearing her friend’s afflicted roars, Shira requests that we put him out of his misery in her place, though we can still have the sequestered medial’s aid during our second battle with Midir in the Lower World through summon signs. As far she is concerned, it is better to put him down now than wait until he even forgets the pact — the description for the blade symbolizing him does acknowledge that it will inevitably fall apart with its sheath. Let him die with the dignity of having defended Filianore from the Dark to the very end.