Nagoriyuki is a tall, heavily built, dark-skinned man with blue eyes and thick, shoulder-length Dread-locks tied into a ponytail. He wears a white coat with purple lining decorated with silver studs and snaps in the style of a haori, with only his right arm through the sleeve; the back of the jacket is emblazoned with a red kanji 心 (kokoro?, heart) and the word "HEART" beneath. This is worn over a simple orange robe cinched at the waist by a red obi and three leather belts, which is likewise half-removed. Beneath this is a long white waist cloth matching his jacket, with several purple and blue straps embroidered with crosses and the phrase "KEEP OUT." He also wears white fingerless gloves, black leggings, and simple gray sandals.
His white mechanical helmet resembles a hannya mask with elongated horns and a rictus grin. In place of eyes and a nose is a featureless white surface marked with the same red kanji that appears on his coat. The helmet can automatically disassemble, retracting behind his head. He also carries a traditional daishou pair of swords sheathed at the hip, with the oodachi locking into its scabbard via a mechanical apparatus in the hilt.
As noble as he is, he is also a kind man, often being willing to provide advice to those he defeats in battle much akin to Slayer, though he often expresses regret and no ill will towards others when it comes to his past being a puppet of Happy Chaos' bidding. Unlike Slayer, he seems to be more active in expressing his desire to help others in spite of having as little worldly-attachments as he does.
Nagoriyuki is a Nightless samurai and the retainer of a man named Kazusanosuke. During the Crusades, he encountered Happy Chaos, who used his powers to force him to do his bidding. At some point after these events, Nagoriyuki paid a vast sum to rent out the basement level of a luxurious high-rise in Illyria, where he spent the next several decades in meditative hibernation.
Guilty Gear -Strive-
Nagoriyuki is found and awakened by Chaos, who once again uses his binding magic to force him to be his bodyguard, since he is the only person who knows his weakness. During the ensuing events he is forced to fight on behalf of Chaos and I-No, and Chaos also copies the unique properties of his blade to create bullets that slows health regeneration's speed for short periods. His ability to use Gamma Blade surprises Chipp Zanuff during their first encounter.
Through these battles, he develops a rivalry with Sol Badguy, telling him his flaws in battle as they fight. However, in their final battle, Nagoriyuki praises him and breaks free of Chaos's control, allowing Sol to defeat him, but sadly have no time to ask him about Chaos' weakness, as Sol is in hurry with US President Vernon E. Groubitz, and the Gear Maker Asuka R. Kreutz to escape from Chaos, but instead, tricking him into being trapped inside the air ship White House's PEOC escape pod and got rid of him.
However, when the real Chaos is revealed to still be aboard the airship, and uses the Tome of Origin which fused with Asuka to fuse the former with I-No, to restore the witch's full godlike power, Nagoriyuki is properly freed from Chaos' control.
In the final battle against a godlike I-No, he returns to help Sol (now simply a 'human' named Frederick Bulsara), Ky and Axl Low find and expose her weak point, allowing Sol to destroy her with his Outrage cannon. With Chaos and I-No gone, Nagoriyuki's whereabouts are unknown.
Like Slayer, Nagoriyuki is a vampire, and thus endowed with immortality, superhuman speed, extreme durability and godlike strength. Unlike Slayer, however, Nagoriyuki fights using a wakizashi along with a large, magical katana (styled akin to an oodachi or a tachi relative to his own size) that is customized to prevent wounds inflicted by it from healing (as seen in the Story Mode of Strive, where several of his attacks temporarily negated Sol's accelerating regeneration). He can also cause his attacks to send energy waves, with the same effect as being hit with the katana itself, making him dangerous even from afar.
Nagoriyuki also possesses two unique abilities. One of them is being able to sense the weak points of his opponents (which is how he knows the weak point of Happy Chaos). The other, known as Blood Rage, increases his combat abilities even further, while also sharpening his fangs, similar to vampires in other media.
Gameplay wise, Nagoriyuki is a character with very high range and damage, which is balanced by low mobility: he can't dash forward or backwards, both on ground and on the air. Instead, he has access to a command dash known as Fukyo, which is very similar to Slayer's ground dash in previous games. He also has access to an unique resource (the Blood Gauge) which fills by doing special moves, and is depleted by hitting the opponent. The more filled the gauge is, the more damage, speed and range his Heavy Slash attacks have. However, filling the gauge makes Nagoriyuki enter Blood Rage mode, where he has amazing range, speed and damage; at the cost of not being able to cast specials and losing 50% of his max health over time. He is also very vulnerable when he enters this mode for a long while.
- Nagoriyuki's name may be an homage to the famous 1975 folk song "Nagori Yuki" (なごり雪?) by IRUKA, originally performed in 1974 by the band Kaguya Hime. The song has been covered by many prominent Japanese pop and rock artists in the decades since it was written.
- Before Nagoriyuki performs Wasureyuki, an image of Gashadokuro appears as a reflection on his odachi; upon finished, a fragment of The Great Wave off Kanagawa appears in the background, and a text appears: 至誠通天 ("shisei tsuuten"), which roughly means "sincerity passing heaven": it is based on a Chinese proverb/precept that made its way to Japanese martial arts in the form of 至誠天に通ず ("shisei ten ni tsuusu"; "sincerity moves through heaven", describing that it can touch/move the heavens), particularly kenjutsu and kendou.
- Nagoriyuki refers to his master using the name Kazusanosuke, one of the pseudonyms of Oda Nobunaga.
- When discussing Nagoriyuki's inspiration, Ishiwatari said that he is based on a historical figure; this is most likely Yasuke, a samurai of African descent who was one of Nobunaga's retainers.
- His theme, What Do You Fight For, pays homage to "Come Together" by The Beatles, and its chorus resembles that of "Junkyard Dog" by Winger.
- Nagoriyuki (名残雪?) is Japanese for "lingering snow," a sentimental phrase referring to out of season snowfall during the spring. Likewise, all of his techniques have a snow-term-naming motif, with his Zansetsu being the only named-technique of his written in on'yomi instead of kun'yomi.
- In a special interaction Nagoriyuki can have with Chipp before a match, the two imply that Nagoriyuki had some relationship with Tsuyoshi. In the Story Mode, Chipp is also surprised to see Nagoriyuki using a technique (his Zarameyuki) resembling his own Gamma Blade.
- In the data-mined files, Nagoriyuki has a special interaction with Slayer where he asks the latter if he was also a Nightless. He also states in his win quotes that his master is actually stronger than Slayer. His intro quote with Sol Badguy also implies that his master is a Nightwalker as well.
- Nagoriyuki's horned mask bears a strong resemblance to the rabbit-headed minions Happy Chaos brainwashes, with the horns also resembling Happy Chaos' own.