For the first time since he got it, Kahn was now using the Hero of Fire's divine weapon aka Amaterasu.
Currently, he only had partial ownership of it and the Divine Weapon itself hadn't completely submitted to Kahn as if it had a sentience of its own.
Kahn couldn't even store it inside his Dimensional Domain because this thing would literally burn everything and everyone it touched.
Thus, Kahn could only keep it inside the True Dimension and subconsciously carry it with him since even the laws of space couldn't destroy the divine weapon. The plus point here was that Amaterasu also couldn't harm anything from the real world.
The only problem here was that the current Kahn couldn't use it for more than one attack based on his current control on the weapon and his rank.
If he had complete ownership… maybe he'd be able to use it just like Axel did during their fight.