u/slaaydee

Game	Japan Release Date	Gap Since Previous Mainline Game
Disgaea: Hour of Darkness	Jan 30, 2003	—
Disgaea 2: Cursed Memories	Feb 23, 2006	~3 years, 24 days
Disgaea 3: Absence of Justice	Jan 31, 2008	~1 year, 11 months
Disgaea 4: A Promise Unforgotten	Feb 24, 2011	~3 years, 24 days
Disgaea 5: Alliance of Vengeance	Mar 26, 2015	~4 years, 1 month
Disgaea 6: Defiance of Destiny	Jan 28, 2021	~5 years, 10 months
Disgaea 7: Vows of the Virtueless	Jan 26, 2023	~1 year, 11 months

Right now we are 3 years 3 months, some odd days since Disgaea 7..

Obviously the gap between 5 and 6 was the longest, it is also when they switched from 2D to 3D so it would make sense. Not sure what happened between 3 and 4 though it was another generation jump from PS3 to PS4.

Hopefully we get Disgaea 8 within the next year..