Drakes Arc Weapon [WIP]

Arc Weapon name: Shiro Nokogiri
Arc Weapon rank: Basic Arc Weapon
Description:

Shiro Nokogiri:

Arc Weapon ability: "Ripper"
Description: The sawblades of Shiro Nokogiri become active, acting exactly how a real saw would though this one is much bigger and in the form of a sword. When 'Ripper' is activated it increases the amount of damage Shiro Nokogiri causes and also increase it's ability to pierce things such as armor and heavy defenses, allowing him to easily cut things that were once not to easy to cut through.
Duration and Cooldown: 4 posts/5 posts.
Strength: Shiro Nokogiri is a rather heavy weapon and thus, its melee strikes are heavy and powerful, easily knocking back opponents, with it's ability it's piercing power can also be greatly increased allowing it to tear through armored flesh and steel as well.
Weakness: What is the weak points to using this Arc Weapon? There is no required set amount but you must be reasonable.