⚓ Uncharted waters This page covers content beyond your reading progress — it begins around chapter 613 .
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Mato Mato no Mi
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Vander Decken IX ’s power, called the “Mark-Mark curse” on-page (Ch. 613 p. 9): “He can hit any target he aims at.” Whatever he throws homes in on its marked target regardless of trajectory — the Rose Axe he hurls at Princess Shirahoshi misses, curves back, and keeps coming (“It’s coming back the other way!” , p. 3). The curse is what confines Shirahoshi to Shell Tower : every week Decken throws another homing weapon at her, so she can never go outside. Decken also avoids skin contact — he refuses a handshake (“Oh? Looking for a handshake? That would be bad,” p. 16) — a tell tied to a touch-to-mark mechanic.
Ch. 613 p. 3, 9, 16 — the “Mark-Mark curse”
Named on-page by Shirahoshi as the “Mark-Mark curse” : anything Vander Decken aims at and throws cannot miss its target. The full “Fruit”/Japanese name is not given this chapter; the power is shown via the homing Rose Axe and Decken’s refusal of skin contact.
Ch. 615 pp. 7, 11-13 — the curse’s full mechanics
Vander Decken IX narrates the power in full: his palm marks a target, and anything he throws homes onto it and follows it anywhere — “even to the depths of hell,” changing direction mid-air and chasing through water. He can hold two marks at once, one per palm (p. 13). His right palm has been locked onto Shirahoshi since he touched her ten years ago (“hasn’t washed my right hand” ) — the cause of years of weapons raining on Ryugu Castle . The cost of being a Devil Fruit user: he is a fish-man who can no longer swim (p. 7). The “Mark-Mark Fruit” wording is the queue’s reader rendering; canonical basename held at Mato Mato no Mi.
Fish-Man Island — the ark thrown (Ch. 637 )
The Mark-Mark power’s scale ceiling is shown to be effectively unlimited: Vander Decken IX has marked and thrown the colossal ark Noah at Shirahoshi , and it homes onto her exactly as his letters and axes did — “once I’ve thrown something with these powers, it won’t stop until it’s hit something or obliterated its target!!!” The thrown object follows the target off-course when she moves (p. 17). Confirms there is no size limit on what Decken can weaponize via a single touch-mark.
Fish-Man Island — the marker-death question (Ch. 638 )
Ch. 638 pp. 2-3, 19 — the curse scaled to an entire ark
Decken applies the Mark-Mark mark to the colossal ark Noah (in addition to his decade-old mark on Shirahoshi ), turning the whole vessel into a homing projectile that chases the princess. Confirms the power scales to objects of arbitrary size, limited only by the two-marks-maximum rule (one per palm). Hody Jones ’s on-page question — “If you die… what happens to the ship, Decken?” (p. 19) — frames the open mechanic: whether the homing persists past the marker’s death.
Fish-Man Island — the mark turned on an ally (Ch. 639 )
The mark is applied offensively against an ally for the first time: Decken brands Hody Jones with a left-hand touch — establishing the fruit’s use as a betrayal/assassination tool, not only the Shirahoshi obsession. The removal limit is stated aloud — “if you die here, the effects of your power will wear off” — re-arming the marker-death mechanic flagged Ch. 638 .
Fish-Man Island — consciousness limit + re-targeting (Ch. 640 )
Ch. 640 pp. 16-17 — consciousness limit + re-targeting
Two new on-page mechanics: (1) the homing only holds while Decken keeps “a sliver of consciousness” — knock him out and the thrown object stops tracking and drops (“As long as he’s got a sliver of consciousness left, that ship won’t fall!!”, p.17). (2) Decken re-marks a fresh target with his left hand mid-fight (“You’re my left hand target now, buddy boy!!”, p.17), restating the one-mark-per-palm rule from Ch. 615 and using it to redirect the thrown ark Noah onto Luffy / the island.
Fish-Man Island — the marker KO’d, homing stops (Ch. 641 )
When Decken is knocked unconscious his active steering of the marked ark Noah ends (“Decken’s powers have worn off… Noah will now plunge straight downward”): the ark stops homing on its target and simply falls, confirming the Ch. 640 consciousness-limit — the marked object’s pursuit is tied to the user’s conscious hold rather than continuing autonomously after a single throw.
User chain
Power limits & weaknesses
(Water/sea immobilization is universal.)
Two marks maximum — one per palm (Ch. 615 p. 13).Marking appears tied to physical contact — Decken refuses handshakes (Ch. 613 p. 16) and notes his right palm has stayed marked on Shirahoshi for ten years because he “hasn’t washed” it (Ch. 615 p. 13), implying a touch-to-mark mechanic and a possible mark-removal limit. (Mechanics not fully spelled out on-page; forward of this window.)
Consciousness-dependent: the homing fails if Decken loses consciousness (Ch. 640 p.17; paid off Ch. 641 p.2 — KO’d, his hold on Noah lapses and the ark drops straight down) — the Chekhov tell that KO’ing him is how to stop the ark.
Lore & theories