Chi Chi no Mi

The Oni Oni no Mi, named for the phrase onikakushi, "spirited away by demons," is a Paramecia-type Devil Fruit which allows the user to instantly switch places with anyone they've touched. It was eaten by Saeko Suzuki, first mate and Swordsman of the Elven Pirates. The name of the fruit relates to Arthur's epithet and the game of tag, onigokko.

Appearance
The Oni Oni no Mi resembled a red durian with spirals around the outer skin. Inside was a dark blue flesh with similar spirals. Like regular durians, it smelled horrible, but also tasted so.

Ability
The major (and indeed, only) strength of the Oni Oni no Mi is that it allows Arthur to switch places instantaneously with anyone he's ever touched. If he has "tagged" them, then the tag cannot be undone, even if they drop underwater. The swapping power of this fruit may seem like nothing spectacular in comparison to the incredible abilities of some other fruits, but for someone like Arthur it is invaluable. By surveying a battlefield, he can see where he should be arrange his crew so that they can most effectively use their strengths. It is in this way that slow or hindered crewmembers like Rayden or Faust (when not touching his bowl) can move around the battlefield as quickly as Mellifera. Although observation begs to differ, Arthur can only swap his own place with someone else's, not the places of two people. This can still be accomplished in a flash, though. Say Person A stands on the left, Arthur in the center, and Person B on the right. To switch Person A and B's places, Arthur can swap with Person A, then B, the A again, so that he is back in the center and A and B have been switched. One interesting quirk about this power is that a person's momentum and position is unaltered in the swap, though they are turned to face the same way as Arthur was when he initiated the switch, and vice versa. If an opponent charged forward with a flying kick, Arthur could face the ground and switch places with the opponent, so that they would smash directly into the ground at their full speed. By rapidly shifting around, Arthur can create chaos and lead a crowd of opponents into stabbing and shooting each other by having them aim at him and switching places with another opponent at the last moment. A quirk about this Devil Fruit is that, like most Devil Fruits, it affects Arthur's clothes. When he tags out, all of his clothes (including his hat, little dagger, and Excalibur if he is wearing him) will warp with him, and the opponent's clothes and equipment will likewise. But any external attachment, such as handcuffs, will not follow him. This can be used to very easily and effectively trap opponents.

Weaknesses
The Oni Oni no Mi's weaknesses are fairly few, namely because it has few strengths to begin with. The main weakness is that Arthur can't switch places with anyone over 250 meters away from him, so he can't just jump back to his home village whenever he feels like it. In addition, while he obviously can't switch places with someone when he's underwater or touching Kairoseki, he also can't switch with anyone else who is underwater or touching Kairoseki, even if he isn't. He also can't switch places if the person he would switch places with is too large to fill the space they would then find themselves in, like a giant into a small room. On that note, although he is able to switch with large people like giants (though this is tricky, since he'll appear at their center point and likely have a distance to fall,) if he tries to switch with a Logia fruit user, only a human-sized cutout of their body will be taken away from their expanding element. It will be the same size as their normal form, and depending on how the element packs together may even force them to solidify for a moment, but it often leaves Arthur surrounded by and at the mercy of the Logia user's element. Other than this, standard Devil Fruit weaknesses apply.

Attacks:
Tag Out: (タグ アウト, Tagu Aoto): The most basic technique where he simply switches places with his target. Usually an ally. It is differentiated from Tag In mainly because the focus is of Arthur moving away instead of someone else taking his spot.

Tag In: (タグ イン, Tagu Inn): Another basic technique in which Arthur's allies (or enemies) launch attacks at him, only for him to switch away with an opponent at the last moment. Against enemies that rely on projectiles, it is possible for them to fire on him and then take their own attack as he tags them in.

Castling: (キャサリング, Kyasaringu): A quick combination of Tag Out and Tag In in which he switches himself into the place of one target, then out and away with a second. Essentially, the point is so that the second target takes the place of the first.

Dizzy Swap (デジ スワプ, Diji Suwappu): A technique best executed with decent distance, and most effective if Arthur and his opponent are either facing each other or away from each other (that is, not in the same direction). By rapidly switching places with the target and back again repeatedly, the target will become very dizzy and confused by the changing viewpoints. It can be countered by simply closing ones eyes, though usually it happens so fast that the foe is left unaware of the tactic until it is finished. Although Arthur can swap places dozens of times in a second, in order for the target to register the change it must be done slower than this.

Speed Saver (ハズミ セバ, Hazumi Seba): A technique usable to protect an ally or damage a foe. Because a person's momentum is conserved but direction changes when Arthur tags in or out, Arthur can switch places with an ally falling out of the sky just before they hit the ground, redirecting them parallel to the ground so that they can regain control and slow down. He can do the reverse as well, so if a foe is charging with great speed he can lie face-down and switch with them, so they smash into the ground with their full speed.

Zugzwang (ズクズバング, Zukuzubangu): Basically just a series of Tag Ins, but it is surprisingly effective against a large crowd. If he can make the appropriate touches, Arthur can appear in the center of a crowd of enemies. When they move to strike him he can tag away, letting their comrade take the hits and setting up to repeat the action. The damages caused by friendly fire are ancillary compared to the chaos this invokes within the enemy lines. The name comes from a German word meaning "compulsion to move," describing a chess scenario in which the player would wish not to move because any action is disadvantageous, as is any enemy attack when Arthur is in their ranks.