Armament Haki is a suit armour equipped for 2 purposes; to force the body of a Logia into solidity, and to amplify destructive power & defensive durability through the Hardening of specifically solid-structured objects (meaning nothing fluid, gaseous or ethereal). This attribute of “Hardening” makes Armament Haki impossible to complement Devil fruit attacks that lack a solid-structure:
- Light based attacks:- Hardened Light? Light can’t be hard.
- Fire based attacks:- Fire can’t be hard, it’s a plasma.
- Smoke based attacks:- Smoke can’t be hard, it’s a gas.
- Mero Mero based attacks:- Mero Mero attacks are not solid.
Simply put, it only complements solid-structure beings, or objects; attacks based on magic or ethereal have no Armament utility.
Not only does Armament Haki not compliment some attacks, it also overrides any ability that turns the user’s body into something that’s not absolutely solid or possessing a solid form; Sabo’s fist is covered in flames, he proceeds to cover his fist in Armament Haki, it returns to human form and then takes on the Armament Haki coating.
Bare in mind that someone like Jozu or Luffy in their forms are still solid, so Armament Haki will work as usual without complications.
How Armament Haki affects Logias
Armament haki can only harden things that are of solid-structure, Logia in general are not solid-structure (not to state that some Logia do not possess solid properties too), therefore when they use haki, they regress to a solid form as can be noticed. To simply put it, Logia (who are limited to non-tangible forms e.g. Gas Logia) can use Armament haki, but not mix it with anything in a gaseous or liquid state which is why the fist is not a smokey Armament Haki claded fist in Smoker’s case, but regressed to a solid fist with Armament Haki.
Occasions a Logias uses Armament Haki over Ability
A Logia will only use strictly employ Armament Haki if:
- Their ability assuming it has no solid variation isn’t strong enough to deal damage, so a weapon or fist claded in Armament Haki becomes more ideal. It’s also confirmed Ace was indeed an Armament user before he got into the New World.
Note that Logia who can use Armament with their abilities (if it possesses a solid variant) will use it just like every other Armament user.
Hierarchy: Logia fruit relationship
The different relationships are…
- Superiority relationship:- This is the instance where 2 Logia DF share similar properties, but one is superior; Magma can quench fire and render fire’s ability to burn redundant (being that magma’s a semi-liquid) implying ability to smother fire, this results in the fire user getting burnt and ultimately losing. The other explanation assuming smothering isn’t the deal here would be that Magma can take on a solid form allowing Akainu to make use of Armament while Fire can’t, therefore, superiority over Ace.
Only the inferior Logia DF type (Fire) must switch to haki in such a situation to stand a chance assuming the smothering rationale doesn’t work, but I think it does have relevance because Oda tends to be scientifically in these instances.
- Antagonistic relationship:- Ice nullifies Magma & Magma nullifies Ice; Aokiji and Akainu share such a relationship so it’s a battle of attrition. They can both hurt the other without using haki and with their abilities to produce their elements, it’s no surprise this battle lasted 10 days.
No haki would be required; natural enemies.
- Symbiotic relationship:- This is a relationship between 2 Logia DFs that can’t really hurt each other and in a sense are harmonious in the presence of each other; neither can hurt the other.
Such a fight would require haki or the fight would remain a stalemate indefinitely.
The states of matter determine whether a Logia can blend their ability with Armament Haki. Hierarchy determines how Logia will fight the other; with Armament Haki or without need (implying optional) to rely on Armament Haki. Even in the event that 2 Devil fruits have a symbiotic relationship, or one of superiority, relationship between abilities doesn’t determine the superior opponent in terms of physical strength & Armament strength, it simply determines the limitations as to how one will fight from a DF perspective.
*Theory by HPsyche