What say you if Luffy loses an arm along his quest for One Piece?
In the One Piece universe, losing a limb is not much a big deal at all. Look at Shanks, Zeff, Kuzan, Kyros and, to a certain extend, Crocodile and Kid. In some ways, they are able to negate the loss of limb one way or another, and most of the time were as strong or may even be stronger than before.
Here is how it goes. Sometime later in the series, Luffy had to sacrifice his arm (left or right) in a fight. But what turns out after that was his remarkable and emormous willpower - one of his critically strongest trait and the direct driver of haki - caused his own haki to level up a notch, seemingly replacing his lost arm with an invisible one.
In the mind's eye of his opponent, Luffy's invisible haki arm act as if he is physically complete, whereas in reality's eye, Luffy only has one arm. His haki arm needs to be "activated" for use, of course.
When Oda draws, during a fight he will draw as if Luffy had full limbs in the eyes of readers (us) and opponent, but if he had to draw it from the eyes of bystanders (like Nami or Chopper watching from a distance), it will be seen as he is only fighting with one arm. During casual times, Luffy will be drawn with one arm (as his haki arm was not activated). You get the gist.
There are things he can and cannot do:
- strike a person with the haki arm during a fight (e.g. haki punch)
- block an incoming attack with it (like any normal busoshoku haki style)
- able to feel what the haki arm, hand or fingers touched (kinda like a sub-ability of kenbunshoku)
- stretch and send his haki arm into dangerous substance like Shinokuni (despite his poison immunity) or some future super-duper-uber-ultra toxic chemical weaponery because it is not a physical arm to begin with
- his haki arm may be able to out-perform his real arm because the limit of his haki arm is pretty much the limit of his haki itself (E.g. stretch longer / further than real arm, bigger in size compared to real Gear Third fist, strikes even faster compared to Gear Second strikes)
- haki arm should be able to withstand a force of elemental attack (like Sakazuki shooting a direct magma punch, the haki arm can block the attack like a wall as far as Luffy's haki level can withstand)
- pump up to Gear Second with the haki arm (the activation of Gear Second cannot work without real blood pump to the heart via real blood veins)
- use the haki hand to hold weaponery e.g. sword or shield (though Luffy fights barefists to begin with)
Because New World opponents and later, second half of the series opponents will generally be very haki efficient, many of them will be able to sense (hence "see") Luffy's haki arm during a fight, making it as if Luffy is in full normal body, thus Luffy will not be at any disadvantage (but may even gain some advantage with some of the "Can do"s above).
In the end, he will reach the same legend like that of Shanks - physically handicapped but does not make him any weak or less bada$$.
So, what do you think of this?