An electrical demon from Movieland's Underworld, Alastor appears as a recurring boss, and sometimes as a playable character. He is also known as "Blade Master Alastor", "The Midnight Thunderboy", "Stylish Alastor", and occasionally by the nickname Al.
Though he is originally allied with Jadow, Alastor doesn't give much thought about his position, but instead longs to seek out "the ultimate battle". He sees himself as the arch-rival of Viewtiful Joe, and always appears with the intent to defeat him. Alastor gave Joe the title "Viewtiful", after seeing him in battle. He is voiced by Mikey Kelley in the games, and Ross Lawerence in the anime.
In all media, Alastor mainly appears in "Blade Master" form, as a humanoid figure in purple spandex and light body armor. He wears a helmet with a pair of purple ibex horns, and has wings and a pointed tail. In Viewtiful Joe and Viewtiful Joe: Red Hot Rumble, he also appears in an un-Henshined Stylish form, where he has pointed ears and spiked black hair, and wears a black suit with a white stole embroidered with winged skulls. He is transformed by the Black Film into a more bestial demon form called Underworld Emperor Alastor in Viewtiful Joe 2.
In the Devil May Cry universe, Alastor is the manifested spirit of a sword found by Dante in the original Devil May Cry game. Alastor's sword, lightning and many of his moves in the Viewtiful Joe games are taken from the DMC game. When Dante fights Alastor in the PlayStation 2 version of the original Viewtiful Joe, Alastor accuses Dante of treating him badly and forgetting about him. Dante responds by saying that Alastor "really knows how to hold a grudge". In Viewtiful Joe 2, Alastor says his line from the original Devil May Cry when Dante first encountered the Alastor sword; "I am Alastor. The weak shall swear eternal loyalty to me!".
- Alastor has his own version of Six Majin, Joe's gigantic personal robot, called Rex Majin. It appears in Viewtiful Joe: Double Trouble!.
For more of this character, see their gallery.