Corrupted by the curse of the Holy Grail, this is the merciless side of the King of Knights.
Or perhaps this is the true nature of the "Ideal King" that King Arthur sought to be.
Altria controlled her own power and held back, but in this state, she wields her immense power without hesitation.
She's said to be the most violent breed of all the Artoria types. According to rumor, Artoria evolves into this form if she's fed enough junk food. Her eyes are colored gold.