Doom Axe 
The buster, which devours enough souls, becomes the Doom Axe, gives the bearer more seductive power, and requires more cost. Once it is grasped, it seems to hear a voice whispering in my mind, "to split the shackle of reason, embrace the abyss of power."
|Atk + 160|
For each level of [Skin Tempering] is learned, Extra Fire Dmg ＋10%
When Strength reaches 50, Atk ＋10%