The Japanese version of Fate/Grand Order is running the Csejte Halloween Trilogy Ultra Deluxe Compilation event, which will allow players the chance to obtain three free Servants. The event will run from October 6 to October 31, 2021. This is a combination of three past Halloween events — Halloween 2015, Halloween 2016, and Halloween 2017. However, you can only view the main story quests. This event will not have any farming quests.
Players can obtain Elizabeth Bathory (Caster), Elizabeth Bathory (Saber), and Mecha Eli-chan as rewards throughout this event. These Servants were free during their respective Halloween events, so players who missed them had to wait until future re-runs.
When you finish the story quests for a specific year, you will get its corresponding Servant. At a later Halloween event, you will get the chance to obtain extra copies to upgrade Noble Phantasms. If you already played through these events and have a maxed-out version of the free Servants, you will receive a Rare Prism instead.
Currently, the Halloween banner for Fate/Grand Order features Servants who played an important part in the Halloween stories. For example, you have a higher chance of pulling Wu Zetian, Nitocris, and Vlad III. Cleopatra, who is a limited Servant, is also in the banner. Fate/Grand Order recently ended its Chaldea Summer Adventure! event. Players had the chance to pull for limited Servants, as well as get a free Leonardo da Vinci (Ruler).
The Csejte Halloween Trilogy Ultra Deluxe Compilation event will run from October 6 to October 31, 2021 on the Japanese Fate/Grand Order server. Fate/Grand Order is readily available on mobile devices.