Nanashi

, also known as, is a foreign Goddess swordsman that started to train the king of Camelot, Arthur Pendragon.

Appearance
Nanashi has long, dark hair and eyes, with the former being kept in a simple ponytail that has a small section fall at the left side of his face. On the back, Nanashi has four scars from where his wings were before losing them. He wears a light, slightly wrinkled kosode with forearm-length sleeves, a patterned obi sash around his waist and a pair of dark hakama. At the left side of his waist is his katana tucked into the obi. He is also seen chewing on what appears to be a twig.

Personality
Little is known about Nanashi's personality. However, he is shown thus far to be a quiet man who seeks great challenges.

He is shown to be a loyal ally, especially to Arthur, whom he considers a worthy master to serve. In battle, he is an honorable warrior.

3,000 years ago
Nanashi was a warrior of the Goddess Clan who at some point decided to abandon his master as well as his devotion to the Supreme Deity, losing hope as he saw how the gods turned them against each other in a meaningless battle. As punishment, his wings were cut off and he was banished. He spent the next millennia wandering the world unable to find a reason to live.

Great Fight Festival arc
Nanashi came from an eastern country who drifted to Britannia. After accepting the invitation to participate in the Great Fight Festival at Vaizel perpetrated by Gloxinia and Drole of the Ten Commandments, Nanashi entered the labyrinth where he encountered an Earth Crawler and killed it with relative ease, saving some few groups of knights who took notice of his attire foreign to them in Britannia.

Upon being asked by one of them of his identity, Nanashi simply answered that the challenge lies awaited for him before proceeding on the depths of the maze where he finally reached the finish line and met up with the rest of the several contestants who also arrived including the Seven Deadly Sins themselves.

When Drole and Gloxinia start the festival and divide everyone in pairs, Nanashi is paired with Arthur. The young king presents himself kindly saying that he is happy to be his companion. After Drole and Gloxinia were attacked by Escanor and Meliodas, Nanashi is taken hostage by Drole along with all the other participants, until Gilfrost manages to teleport everyone to Liones.

Defensive Battle for Liones arc
One month after the events in Vaizel, the Demon Clan began its conquest of Britannia. Nanashi helps Arthur in his attempt to regain control of Camelot, which had been taken as headquarters by the demons. He, along with Arthur and other knights face a horde of Gray Demons. Nanashi eliminates several of them and together with Arthur manage to defeat them all. Upon hearing Cath speak, Nanashi seems to sense something in him, claiming that Arthur will not die while Cath was with him.

When a troop of Blue Demons appears to attack them, the group is forced to undertake the withdrawal.

Prelude to the New Holy War arc
After a failed attempt to free Camelot, Nanashi helps Arthur to hide all the surviving civilians in an underground hiding. When Arthur come along with Orlondi, Nanashi informs him of his recognition that fifty five demons were already released from the seal. Arthur reveals that he has already eliminated half of them, gaining the praise of Nanashi for the growth he has had in recent months. There, Nanashi says that it is time to carry out his plan to infiltrate into the castle himself to recover the holy sword, Excalibur.

Epilogue arc
In the ruins of Camelot following Cath's defeat, Orlondi is able to break out of the underground bunker and is shocked to see what remains of Camelot before Nanashi calls for his help in getting the civilians outside. The two of them lay the unconscious people onto the ground where Orlondi commends him as the people would've died if not for him.

Nanashi, however, blames himself for not being able to save everyone as he looks to the few people who were killed in the attack but Orlondi tells him he shouldn't blame himself for that but is surprised to see four scars on his back and realizes that Nanashi is from the Goddess Clan, his wings having been torn off.

He claims it to be an old story and now is nothing more than a wandering samurai without a master but notices something in the distance and the two of them are surprised to see none other than Merlin and Arthur flying to them as Orlondi goes to greet them, while Nanashi watches with a smile.

Sixteen years after the Holy War, Nanashi disappeared from Britannia along with the other survivors of Camelot, settling in the new Camelot and serving as one of Arthur's Holy Knights under the name Tomintoul.

Demon Realm arc
Nanashi is part of the group led by Mortlach that is sent to deal with the Four Knights of Apocalypse.

Following them through the hidden entrance to the Demon Realm, they are all thrown into the void by the relic-portal's filtration system. The Holy Knights save themselves by summoning an Arakdo.

Meeting to decide how to proceed, everyone notices something strange about Rosebank when he refuses to speak, claiming to have been infected with the Demon Realm's miasma. Upon attacking Rosebank, this one manages to incapacitate two of the knights, being healed by Nanashi's Invigorate. Rosebank ends up revealing herself to be a disguised Gawain. After Gawain trapped his four companions in her Super Slow spell, Mortlach manages to distract her with words allowing Nanashi to catch her off guard and knock her out from behind.

Six days after meeting with the real Rosebank and agreeing to wait for the enemy to make a move, the Holy Knights follow the Albion that the Four Knights of Apocalypse were riding, soon noticing that Nanashi's Saint Coat that had been protecting them until then is no longer effective against the negative energy of the Behemoth. That is why they decide to sneak into the Albion, which seemed to remain isolated, until they are discovered and a battle breaks out in which both groups lose their means of transportation.

The Holy Knights begin to die prey to the negative energy that once again fails to be blocked by the Saint Coat, surprising Tristan that a Chaos Knight can use Goddess magic. After saving themselves by using Gawain and Schwarz's Group hostage to force Percival to save them, the Behemoth is returned to his dream by Percival.

Then, those of the Tristan Platoon try to go to the portal to Camelot that was still open, but Nanashi tries to prevent it with his Hijo no Oroshi, which manages to be blocked by Lancelot. Although Lancelot kicks him flying, Nanashi manages to cling to his arm causing the two to be thrown. Already far from the rest, Lancelot shoots some arrows that forces Nanashi to remove his armor. Confirming that Lancelot was the one who defeated his master Arthur and that neither of them showed his true strength yet, Nanashi reveals his real name willing to fight Lancelot.

Abilities and Equipment
Nanashi is a very powerful combatant, displaying superhuman levels of speed, strength, and precision when he easily defeats an Earth Crawler and a Gray Demon by his lonesome with nothing but a normal blade. He is an extremely skilled swordsman, bisecting an Earth Crawler with ease despite the protective mucus on its skin.

As a Goddess, Nanashi can also use several of their abilities and spells, including their healing magic. His prowess was compared with that of the Four Archangels.

Abilities

 * An archetypal magic technique of the Goddess Clan that counteracts darkness by disintegrating it with light particles. The target is enveloped in a dazzling sphere of light that breaks apart their body.
 * This move allows him to cut almost anything with a single swing of his sword, by rapidly un- and re-sheathing his blade.
 * Flight: Despite having had his four wings clipped, Nanashi still seems capable of deploying them in an ethereal form to fly long distances.

Weapons

 * Nanashi carries around a white katana as his main weapon. Revealed to be one of Dubs' creations, Shirojika proved to be rather durable, as it withstood Lancelot's power, whereas most weapons would break when subjected to it. After his defeat, Nanashi gifted this katana over to Lancelot.

Arthur Pendragon
Nanashi had an odd friendship with King Arthur, the young ruler of Camelot whom he had met as his partner at the Great Fight Festival in Vaizel. While being indifferent to him despite the latter's attempts to befriend him, Nanashi tags along with Arthur to help defend Britannia from the Ten Commandments' onslaught, presumably to seek a much greater challenge from fighting the Demons.

Many years later, Nanashi's loyalty and devotion to Arthur still remain, despite the drastic changes that has happened to the King. Nanashi serves under Arthur as a Chaos Knight, assisting his current plan to exterminate all the other non-human races of Britannia, even when he himself is a Goddess. Although deep down he understands the darkness that had taken over Arthur, Nanashi did not abandon him, knowing that he did not have the power to oppose him and hoping that his old kind self still exist, wishing to find in the Four Knights of Apocalypse those capable of open Arthur's eyes.

Trivia

 * "Nanashi" translates to "nameless, anonymous".
 * Nanashi is a foreigner outside of Britannia despite some samurai elements like Simon of Dawn Roar in the King Arthur-based manga series.
 * "Iai" refers to ', which is a Japanese combative quick-draw sword technique originating in the 8th century. Nanashi is shown to make frequent use of this technique, as he resheathes his blade between attacks.