These are seasonal events that occur occasionally, such as collaboration events or promotions. Sometimes these events come with special bonuses like halved AP cost, increased gold or exp rates and more player exp.
Digital Jack - World Wide Akihabara
A collaboration with the YouTube channel World Wide Akihabara, where the hosts of the channel are promoting the game. They appear in the game as Denpa Units (でんぱユーニット) and can be either captured in their own stages or the special stage, which drops rank 3 psyllium weapons as well as all the denpa units.
There are 6 promotional units for this event.
Lisa - Archbishop (Staves)
Mirin - (Swords)
Nemu - (Axes)
Pinky - (Spears)
Eitaso - (Bows)
Megu - (Firearms)