Alastor is a The legendary sword from Devil May Cry, which has the same properties as Dragon Fang and Tiamat, but with the ultimate attack power and defense and Used by Masamune Date.
Devil May Cry[]
Alastor also appears Devil May Cry. It is also one of the two keys alongside Ifrit that can unlock Dante's inner, unlimited power. It can only be wielded by the "chosen one" who can conquer it, but it is able to grant its possessor lightning speed and aerial capability
Viewtiful Joe []
Alastor's manifested spirit, Blade Master Alastor, appears as a recurring boss and sometimes as a playable character in the Viewtiful Joe series, also by Capcom. It is revealed in Dante's story line of the game that Alastor has left the sword due to Dante's carelessness. Dante responds by saying Alastor "really knows how to hold a grudge." Also, Dante wields the Alastor during his appearances in Viewtiful Joe and Viewtiful Joe: Red Hot Rumble.