Nereus

Biodata

Feature	Value
Name	Nereus (涅柔斯)
Alias(es)	“Vampire”
Species/Race	Fish-Man; appears almost indistinguishable from a human
Gender	Male
Affiliation	Ryugu Kingdom; former associate of the Rocks Pirates
Occupation/Role	King of Fish-Man Island; founder and commander of the reorganized Neptune Army
Status	Alive
First Appearance	Chapter 1

Power Progression

Chapter(s)	Advancement / Reveal	Details
6–7	Hybrid transformation revealed	Demonstrated a distinct Vampire Fruit hybrid form with independently functioning bat wings, enhanced physical traits, and aerial mobility. 6 7
21	Water-combat adaptation revealed	Revealed his self-repairing bubble membrane, which offsets the normal underwater weakness of Devil Fruit users and allows sustained aquatic combat. 21
23	Devil Fruit awakening	Awakened his Mythical Zoan power at God Valley, drawing blood from corpses across the island into a massive blood sphere while greatly expanding his effective range. 23
31	River of Death explained	Demonstrated that souls collected through drained blood can be retained within the River of Death and used as resources for resurrection. 31
99	Secret Art: Blood Burst	Developed a blood-control technique that accelerates a contacted target’s circulation and damages their vulnerable internal organs. 99
114–116	Immortality tested against the Five Elders	Proved capable of repeatedly restoring himself to peak condition while fighting the Five Elders, forcing a stalemate between their respective regenerative abilities. 114 116
177–179, 196	Poneglyph weaponization	Successfully turned Poneglyph weapons into the Red Snake and Black Tortoise through Devil Fruit technology, adding autonomous Mythical Zoan weapons to his arsenal. 177 178 179 196
224	Divine Departure	Learned and used Gol D. Roger’s Divine Departure through Roger’s soul in the River of Death, defeating Douglas Bullet in one strike. 224
248–249	Vampire conversion	Demonstrated the ability to transform others into lesser vampires, granting Ginny enhanced physical abilities, regeneration, blood-draining, and flight. 248 249
362	Observation Haki Killer	Revealed a Conqueror’s Haki-based concealment technique that suppresses opponents’ Observation Haki and effectively removes him from their perception. 362

Background / History

Nereus left Fish-Man Island after learning combat techniques and set out with several companions from the Fish-Man District. Witnessing the slave trade’s devastation of Fish-Man Island, he resolved to overthrow the World Government and end Celestial Dragon rule. His destruction of a World Government slave transport made him a wanted pirate, and his bounty later rose dramatically. 2

He established himself on Beehive Island, where his reputation deterred pirates from threatening his daughter Nanamo. He frequently clashed with Rocks D. Xebec, with one sparring match lasting seven days and seven nights; the two were considered capable of sinking Beehive Island if they fought seriously. Despite his proximity to the Rocks Pirates, Nereus did not share Rocks’s plans for a rapid victory over the World Government. 1 6

During the God Valley Incident, Nereus awakened his Devil Fruit, gathered blood from the island’s dead, rescued civilians, and worked with Kuma’s evacuation efforts. He later learned more about the circumstances surrounding Rocks’s death through the River of Death. 23 24 30 31

After God Valley, he returned to Fish-Man Island and began consolidating its scattered Fish-Man and merfolk population. He overthrew King Pontus, became king, expelled Neptune and the former royal loyalists peacefully, and publicly promised a safer nation. 74 76 77

As king, Nereus rebuilt the Neptune Army, expanded infrastructure, established training systems, regulated passage through Fish-Man Island, and pursued trade security. His actions sharply reduced kidnappings and trafficking around the island. 78 81 83 93 123

His conflict with the World Government escalated into a direct confrontation with the Five Elders. Unable to permanently kill one another, both sides reached a negotiated settlement granting Nereus rights over the Grand Line midpoint and a garrison presence on Sabaody Archipelago. 114 116 119

Nereus later represented the Ryugu Kingdom at the Reverie, where Fish-Man Island entered mutual-support and shipping-security agreements with multiple New World kingdoms. He also continued using the kingdom’s Sabaody presence to protect civilians, advance Ryugu Kingdom interests, and project his authority on the surface. 156 160 163

Appearance

Nereus is a towering Fish-Man whose outward appearance is close enough to human that his race is not obvious. In combat, his Vampire Fruit transformations make his predatory traits far more pronounced.

• Over three meters tall. 1
• Usually appears human, unlike Fish-Men with obvious piscine traits. 1
• Possesses broad, independent bat wings in hybrid form. 6 7
• Develops sharper nails, a more muscular build, and crimson-tinted pupils while transformed. 7 22
• Fights primarily with his hands rather than conventional weapons. 7

Personality

Nereus is strategic, disciplined, and focused on long-term change rather than indiscriminate piracy. His central objective is to dismantle the World Government and Celestial Dragons’ rule, particularly the systems enabling slavery and the exploitation of Fish-Men and merfolk. 2 6

He is protective toward his family, subordinates, and Fish-Man Island’s citizens. He personally safeguards Nanamo, trains younger allies, rescues civilians when possible, and makes the island’s security a priority. 1 16 48 77 83

His compassion is selective. Nereus can be ruthless toward slave traders, pirates, Cipher Pol agents, and Marines he considers threats, often using fear and public displays of force to protect Fish-Man Island’s interests. He is also regarded by World Government intelligence as vengeful and heavily murderous toward enemies. 43 51 89 109 144 248

Abilities & Skills

Vampire Devil Fruit

Nereus possesses a Vampire-themed Mythical Zoan Devil Fruit that grants flight, transformation, blood manipulation, regeneration, and the River of Death. His mastery lets him maintain a distinct hybrid form with independent wings. 6 7 23 249 376

• Can grow bat wings and fly freely. 6 7
• Manipulates blood from dead bodies within a range; living targets are not directly affected by this collection ability. 22 23
• Forms blood weapons, including spears, arrows, swords, and large-scale blood tides. 27 43 116
• Can drain blood from targets, including removing an enemy’s heart and draining their lifespan. 21 43 89
• His Devil Fruit awakening drew blood from corpses across God Valley into a massive blood sphere. 23
• Can transform others into lesser vampires; Ginny gained enhanced physique, self-healing, blood-draining, and bat-wing flight while retaining the ability to swim. 248 249
• His transformed vampires are subject to an implicit command influence from Nereus. 249

River of Death and Immortality

Nereus can dissolve into the River of Death and replace a destroyed body with another restored to peak condition, making ordinary lethal damage ineffective. 31 116

• The blood drained from his victims serves as the medium through which their souls are drawn into the River of Death. 31
• Uses souls within the River of Death as resurrection resources. 31 346
• Can return after catastrophic wounds with his aura fully restored. 116
• Can release souls from the River of Death rather than retaining them under his control. 31
• Cannot be permanently killed unless an opponent breaks through his Haki defenses, destroys his heart while he is in his elemental-like state, and repeats the process countless times. 33
• His immortality allowed him to stalemate the Five Elders, who also possessed regenerative immortality. 116
• High-level souls such as Rocks and Roger retain diminished combat ability if forcibly controlled by the River of Death. 346

Haki

Nereus is an exceptionally advanced Haki user, capable of overwhelming high-level opponents and defending against attacks that would devastate his surroundings. 7 114

• Possesses Conqueror’s Haki comparable to Rocks’s, with highly concentrated infusion around his attacks. 7
• Uses Conqueror’s Haki to screen Neptune Army recruits for mental and physical strength. 82
• Maintains a Conqueror’s Haki barrier that Mars’s wind blades could not penetrate. 114
• Demonstrates powerful Armament Haki, including internal destruction applications. 99
• Can evade observation and remain undetected even by a CP9 chief with rudimentary Observation Haki. 43
• Possesses the Observation Haki Killer, a Conqueror’s Haki application that suppresses an enemy’s Observation Haki and prevents them from tracking him. 362
• Can produce sword-like slashes even with an ordinary blade despite preferring unarmed combat. 82

Fish-Man Physiology and Water Combat

As a Fish-Man, Nereus possesses enhanced strength and underwater adaptability. Unlike conventional Devil Fruit users, he can continue fighting effectively in water. 1 20 21

• Produces a skin-tight, self-repairing bubble membrane that repels water and preserves his combat ability underwater. 21
• The membrane can be continuously replenished as long as he has stamina; its cost is compared to breathing. 21
• Can remain afloat after releasing his grip on the sea surface, despite being a Devil Fruit user. 20
• Can communicate with marine life, a rare ability even among Fish-Men. 30 44
• Persuaded a Sea King to tow his ship through the Calm Belt. 57

Combat Techniques

Nereus combines extreme speed, physical strength, Fish-Man techniques, Haki, and blood manipulation.

• Hell Stab — Condenses Conqueror’s Haki around his fingertips and launches himself like a spear. 7
• Secret Art: Blood Burst — Accelerates an opponent’s blood flow after contact, exploiting the vulnerability of internal organs. 99
• River of Death — A large-scale blood attack that can become a destructive blood tide. 31 116
• Divine Departure — Gol D. Roger’s signature Conqueror’s Haki slash, learned by Nereus through Roger’s soul in the River of Death. 224
• Can fight and defeat Logia users through Haki, as demonstrated against Ace. 346

Equipment / Weapons / Items

• Poneglyph weapons — Uses indestructible Poneglyphs as blunt weapons and sought methods to feed Devil Fruits to them. 81 82
• Red Snake and Black Tortoise — Poneglyph weapons transformed through Devil Fruit technology and deployed as autonomous battlefield weapons. 177 178 196
• Black Tortoise — An indestructible guardian weapon capable of reflecting damage, manipulating terrain, and producing large-scale battlefield disruption, though it is slow-moving and lethargic without orders. 179 196 197
• Flail — Retrieved following his agreement with the Five Elders. 119
• Pluto blueprints — Possesses the blueprints for the Ancient Weapon Pluto and regards them as an important strategic asset. 387
• Tamed sea beasts and Fighting Fish — Maintained for defense, transport, and military training. 4 17 82

Relationships

• Nanamo — Daughter; Nereus is deeply protective of her, trains her, and involves her in Fish-Man Island’s affairs. 1 16 82
• Chloe — Daughter with Amphitrite; Nereus supports her Lunarian upbringing and combat training. 177 179 212 215
• Charlotte Linlin — Ex-wife and Nanamo’s mother; their relationship began after Linlin met the powerful Fish-Man Nereus. 2
• Amphitrite — Lunarian partner and Chloe’s mother; Nereus rescued her from CP9, treated her toxins, offered her shelter, and trained her in Haki. 43 44 48 177 179
• Rocks D. Xebec — Former associate and repeated sparring partner; Nereus opposed Rocks’s broader plans despite their connection. 1 6
• Kaido — Former Rocks associate whom Nereus mentored and repeatedly fought; Kaido recognizes his strength and continues to seek a challenge. 47 231 330
• Sebastian — High-ranking subordinate and Neptune Army commander. 2 83 196
• Babel — Trusted subordinate and God Valley companion; Nereus is notably protective of him. 17 27
• Sunbell — Senior Fish-Man officer entrusted with administrative and military duties. 3 78
• Fisher Tiger — Fish-Man District leader who wished to join Nereus’s crew; later co-led the First Legion. 51 83
• Vander Decken VIII — Former pirate adversary who submitted to Nereus and entered his service; Nereus later used him to test the Black Tortoise’s abilities. 95 178 179
• Douglas Bullet — Defeated by Nereus and compelled to work as a mercenary for the Ryugu Kingdom in exchange for guidance and an annual chance to challenge him. 224 225
• Kuma — Allied with Nereus during the God Valley evacuations and later facilitated his rapid travel. 24 26 95
• Zephyr — Marine adversary with whom Nereus has a tense relationship marked by threats, mutual recognition, and family-related incidents. 109 164 165
• Gol D. Roger — Former associate from the God Valley era; Roger entrusted Nereus with watching over Ace, and Nereus later learned Divine Departure from Roger’s soul. 224 346
• Portgas D. Ace — Roger’s son; Nereus acts as an unwilling mentor and temporarily prevents him from entering the New World unprepared. 345 346

Story Role / Major Arcs

Beehive Island

Nereus is introduced as a feared Fish-Man leader on Beehive Island. He stops Kaido’s drunken destruction, protects Nanamo, manages his crew, and repeatedly clashes with Rocks. 1 2 6 7

God Valley Incident

He travels to God Valley with Babel, awakens his blood power, rescues civilians, confronts a Holy Knight, and becomes involved in the battle surrounding Rocks and Imu’s forces. 17 23 24 30 33

Rise of the Ryugu Kingdom

Nereus returns to Fish-Man Island, overthrows Pontus, becomes king, rebuilds the military, and turns the island into a more secure and organized state. 74 76 78 81

Conflict with the World Government

After repeatedly confronting Cipher Pol and Marine forces, Nereus battles the Five Elders at Mary Geoise. The resulting stalemate leads to a treaty recognizing major Fish-Man Island interests. 43 89 109 114 119

Deep-Sea Expansion and Sea Prohibition

Nereus uses Fish-Man Island’s strategic location to regulate trade and passage, confronts threats such as Vander Decken VIII and Harding, and makes the island’s power impossible for pirates and underworld groups to ignore. 93 144 148

Mentor to the Next Generation

He trains Nanamo, Amphitrite, Luffy, Alber, Chloe, and other younger figures, emphasizing Haki, practical combat, and the need to become strong enough to survive the New World. 48 83 190 215 346

Reverie and Sabaody Archipelago

Nereus brings the Ryugu Kingdom back into the Reverie system, secures international shipping agreements, and strengthens the kingdom’s influence on Sabaody. During this period, he assists Zephyr’s family after a pirate attack and later confronts Holy Knights who cross his path on the archipelago. 156 160 163 164 362

Poneglyph Weapon Program

Nereus pursues the weaponization of Poneglyphs through Devil Fruit technology, ultimately fielding the Red Snake and Black Tortoise in support of the Neptune Army. 177 178 179 196 197

Ace’s Arrival

When the Spade Pirates reach Fish-Man Island, Nereus reveals that Roger asked him to watch over Ace. He easily defeats Ace, teaches him the danger of the New World, and orders the Spade Pirates to remain on the island until they are better prepared. 345 346

Trivia

• Nereus’s bounty was once stated to be five billion Beli during the period when he was known as the “Vampire.” 181
• He can read ancient script and translate Poneglyphs. 44 95
• He knows the locations of all four Road Poneglyphs. 190
• Despite his fearsome reputation, he has no habitual preference for weapons and considers his hands his most familiar tools. 7
• He does not drink alcohol, considering it bitter and mentally dulling. 6
• His crew is composed largely of Fish-Men and merfolk because they find it easier to trust him as one of their own. 2