Disgaea 4 is, as with all Disgaea games (besides D2), a self-contained tale revolving around our protagonist Valvatorez and this Loyal retainer Fenrich.

Valvatorez was once a powerful demon known as Tyrant Valvatorez, however, due to a promise, he has lost most of his power and has been demoted to the rank of Prinny instructor, a lowly role in the netherworld. The netherworld is where demons reside, and you can think of it as the equivalent to hell.

(In case you were wondering, Prinnies are the lowest level denizens of the netherworld and are the recycled souls of humans who need to atone for their sins.)

Whilst training the Prinnies, Valvatorez makes a promise to them that they will each receive one sardine upon graduating and becoming fully-fledged Prinnies. This is the true starting point of our story as Valvatorez, being such and proud and noble demon, never breaks his promises. Ever!

He becomes aware that all his Prinnies are missing only to find out that they are due to be executed by the ‘Corrupternment’ thus being unable to fulfil his promise to the Prinnies. This reason and a little ‘nudging’ from Fenrich is all Valvatorez needs to vow to take down the ‘Corrupternment’.