Makai Wars (Disgaea 2)

Makai Wars is a cancelled Nippon Ichi game, said to star Asagi.

Disgaea 2: Dark Hero Days
Makai Wars appears as a 'movie' starring Asagi whose production Axel was involved in, though after the conclusion of Axel Mode, the movie was canceled, and the film company instead moved on to the sequel. Later, upon defeating Baal in Disgaea 2, a Legendary item of the same name could be obtained.

Disgaea 3: Absence of Justice
The Makai Wars item is in the possession of Baal in this game as well. However, since he has it equipped during the fight with him, you have to steal it from him.

Disgaea 4: A Promise Unforgotten
The Makai Wars item is in the possession of Zetta this time around.

Prinny: Can I Really Be the Hero?
Prinny mentions that he heard Asagi was going to star in "Makai Wars (Pending)." Prinny's response was a suggestion that Asagi's name be changed to "Asagi (Pending)".

Disgaea D2: A Brighter Darkness
The Makai Wars returns in Disgaea D2 as the rank 39 ATK-based monster weapon.

Disgaea 5: Alliance of Vengeance
Makai Wars is the name of one of the rank 40 ATK-based monster weapons. Baal holds one in both fights against him, though his equipment cannot be stolen.