Can Luffy Use Advanced Armament Haki. It looked like some type of demonic aura emanating off Luffy but in any case it mostly likely Haki coming off of him with his rage. The second where Haki is extended towards the weapons for a lack of better word Imbued in the weapons.
By Rei Penber Published Apr 02 2020. Advanced Ryuuou is a far more refined type of Armament Haki which instead of damaging from the outside seeps into the body of the target and destroys it from the inside out. 9 Characters That Can Use Advanced Haki.
9 Characters That Can Use Advanced Haki.
It acts exactly the same way as what Hyogoro described which was to inject Haki into an object to destroy it from within. Luffys Devil fruit may not be one of the strongest but his Haki sure is. With the Advanced Armament Haki not only did Katakuris overpower Luffys but it also made his attacks pack way more punch. Another example is kings haki.