Athera
As time passed, Shiro managed to draft up a few decent prototypes despite the myriad of failed ones. These 5 prototypes gave her a similar feeling to when she used her other attunements such as the Void Star. Understanding that she needed to make sure they worked, Shiro started to test them out against a target and see if the 'element' could kill the target without brute force.
The first 3 were failures as she needed to destroy the armour of the target first. Shaking her head, she proceeded with the fourth prototype.
Looking at her soul sword that now had a metallic handle and guard, she took a deep breath and hoped that it would work.
The test subject in question was the armoured wyvern that boasted an impressive defensive stat. Its main skill was to reflect the damage it took back at the dealer, provided that the wyvern was alive of course and their fighting tactic was to fight a battle of attrition.