Homebrew Demon Weapon Species Details

You may choose your race as you are no different than the "normal" beings of this world. 

Demon Weapon Traits

Weapon Transformation. You have the ability to fully or partially transform into a weapon. When you choose this race when making your character, choose one non-magical weapon from the PHB or DMG to be your weapon form. This weapon loses the heavy property if it had it, gaining the finesse property. As an action, you may transform fully into your weapon form. Your speed becomes 0 and you share a space with whoever is holding you, moving when they move. Alternatively, you may partially transform into your weapon as a bonus action, changing your unarmed attack damage to the damage type of your weapon form and dealing 1d4 damage of that type. Devour. Whenever you kill an enemy, you regain Hp equal to the enemy’s CR (rounded up)+your Charisma bonus.

Weapon Transformation

You have the ability to fully or partially transform into a weapon. When you choose this race when making your character, choose one non-magical weapon from the PHB or DMG to be your weapon form. This weapon loses the heavy property if it had it, gaining the finesse property. As an action, you may transform fully into your weapon form. Your speed becomes 0 and you share a space with whoever is holding you, moving when they move. Alternatively, you may partially transform into your weapon as a bonus action, changing your unarmed attack damage to the damage type of your weapon form and dealing 1d4 damage of that type. (more info in the Demon Weapon Combat section)