Haki and Devil Fruits

Ren raised a finger.

"The first type of Haki is Armament Haki, if I could use it I'd show you, but the basic of this type of Haki is to coat a body part or weapon in spiritual energy which will turn it black."

Artoria tilted her head sideways. "Why can't you use it?"

"Firstly, I need to train my body to a certain degree to actually start using it. Secondly, I don't know how to use this type of Haki yet," said Ren with a slight grin. "Do you understand?"

"Yes," said Artoria while nodding her head.

"Alright then. Moving on, the second type of Haki is observation Haki. This is basically the sixth sense. It allows people to see stuff they can't and dodge things that haven't happened."

"So like instinct?"

"It's exactly like instinct!" Said Ren while snapping his fingers. "You seem to understand observation Haki very well so let me move on to the third type. Conquerers Haki. This is a rare type of Haki that basically makes people submit via sheer willpower. People can only use this if they are born with it. So you won't have to worry about this for the most part."

"Alright. Is there anything else?"

Ren let out a grin. "Indeed there is one more. I call this Nature Haki. This is a special type of Haki that allows one to utilize an element to a small degree. Like sparking your feet on fire from extreme rotation or igniting your fist with flames."

"Won't nature Haki affect the powers of logia devil fruits?" Asked Artoria with a frown.

Ren shook his head.

"Devil fruit users become masters of their own element. Let's say we have a fire logia and a fire nature Haki user. It is nearly impossible to use fire nature Haki to beat a fire logia as the fire logia will have absolute dominion over flames most of the time. Now if fire nature Haki was used in conjunction with a paramecia devil fruit that modified the body in a special way or zoen devil fruit that changes you into a strong animal? Perhaps the tides could change in the fire nature Haki user."

Ren furrowed his eyebrows as he started to fall deep into thought. "… perhaps you could have a flaming bear? Or perhaps a frost owl? A lightning rat?"

After waiting for Ren to finish his monologue for a few minutes, Artoria couldn't help but snap him out of it. "Hello, Ren? Are you there?"

Ren immediately regained his focus and scratched his head with a wry smile.

"My bad Artoria. Where was I?"

"Nature Haki."

"Oh right. Let's see here. Uhhh. Nature Haki is genetic so most people won't have it but it's not as rare as Conquerers Haki. Both Armament and Observation Haki can be learned via training… I can't use any of them right now so I can't teach you them. Any questions?"

Artoria let out a sigh. "I kinda regret learning about this. I can't even use it so what was the point of me listening to this lecture?"

Ren rolled his eyes. "I did tell you earlier that there was no point in learning about it now."

"I guess you were right… wait. If you can't use Haki… how do you have a black katana? I thought those could only be made with repeated use of armament Haki?"

Ren's face became clouded for a moment before turning back to a smile. "The previous owner made it into a black blade."

"Who was the previous owner?"

"Doesn't matter," said Ren. "He is dead."

Artoria and Ren faced each other in silence for a few moments before Artoria broke the ice.

"… Ren-"

"Oh look, we are almost at the island. I should probably prepare for docking."

Ren walked away to mess with the sails while Artoria stared at Ren's back with a complicated gaze before turning to the sky and letting out a sigh.

[A/N: As the chapter title suggests, this chapter was just to info dump how the power system works in one piece for people who haven't read the original manga or watched the anime. I also added in my own Haki of Nature Haki to explain a few stuff in the original manga as well as to explain a few things I will write about in the future. Thanks for reading]