When i played DP, Blaze Crowd was the Raid event of DP. If nothing changed while i stopped playing, this crossover can be completed very easily but not so fast (if Nutaku don't screw things up like the other crossover) because you are supposed to gain Alyssa coins be just doing the event quests (that is just tap in the screen and skip dialogue) and defeat the raid boss that randomly appear. If you did't killed the boss with the first attack, simply call for some help and keep doing the event quests and people will surely defeat the boss for you. Repeat the process until you finish and return to DP only if there is another crossover.
I do recommend play DP on mobile, the desktop version is terrible.