I am so unbelievably confused why this game didn't release after Royal. While nothing in this game contradicts what happens in Royal, the lack of characters like Sumi and Maruki make the cast feel incomplete. It's even more striking when you realize that a lot of these plot points, notably with Sophia and Kuon, are remarkably similar to Royal. What it makes up for it is the quality of the writing, and the incredibly fun dungeons (jails) and boss encounters. As far as Warrior-styled crossover games goes, this one is probably the most complete package.

This is coming from someone who typically avoids the genre at all costs-- let alone touching a series known for the grinding-- but Disgaea 5 nails its gameplay loops and map design in a seemingly accidental perfect balance. The way you can assess each situation with any given party of characters is hardly comparable to much else, and all of the usual progression mechanics allow for "ways of getting there" to accommodate varying skill levels, rather than necessary time sinks. Overload abilities bring incredible nuance to every situation as you figure out how to apply them on the fly. All of these things come together in such a way that still makes it insanely accessible.
Disgaea 5's art style brings its HD hybrid animation to a peak with smooth transitions between attacks, and each ability doing very much with very little. Environments are fantastic but very readable and attacks are over the top and more insane than you could ever expect.
The game's greatest shortcoming is easily the story, something which used to be the highlight of the other Disgaea games, however it was still terse and effective for changing locales. Even that being said, characters don't ever become stale and always have their fun little moments.
Top this all off with my personal favorite soundtrack of the series, and you have a pretty exceptional game for the genre that is still accessible to even the fresher players.