On December 6, DeNA and Crunchyroll Games announced that they will launch a holiday-themed event in the Attack on Titan TACTICS mobile game. The event, titled Fanciful Story Event – Holy Night’s Battle, will officially kick off on December 11, at 1:00AM Eastern (12/10/2019 at 10:00PM PST). The event is slated to run through December 25 at 2:59AM Eastern (12/24/2019 at 11:50PM PST).

Attack on Titan Tactics - Eve of Formal Dress - Banner Visual

Through the campaign, players will be able to complete themed stages to earn rewards, which can be used to acquire the “Eve of Formal Dress” variant of Armin for their party. Folks who log in by December 11, at 1:00AM Eastern will receive thirty “Boxes of Treats” items, which can be used to provide experience boosts to individual units.

Attack on Titan Tactics - Eve of Formal Dress - Armin Visual

Crunchyroll describes the event as:

This in-game event tells an original story that’s set in the time period when Eren Jaeger was in the 104th Cadet Corps. With the entire regiment tired from training and eager to hold a festival for the holidays, Armin Arlelt goes beyond the Walls in search of a special tree that’s required for the festival.

Attack on Titan TACTICS is a free-to-start real-time strategy game based on the Attack on Titan anime. In the game, players are tasked with building their own Scout Regiment, as they do battle against the Titans. The title is available for users on iOS and Android smartphones.

Source: Crunchyroll (Email Communication)