Castrum Lacus Litore is a 48-man raid within the Bozjan Southern Front, where players take on the IVth Imperial Legion. The raid is required to progress through the Save the Queen questline for upgrading Resistance weapons. Storming Castrum Lacus Litore pits you against several boss encounters, each with their own scripted mechanics. Entering the raid itself has some unique hurdles.
Unlock the Bozjan Southern Front and follow the story quests
Before you can enter Castrum Lacus Litore, you have to first unlock the Bozjan Southern Front. Then pick up the story quests you’ll find right at the starting camp. You can only continue with these quests as you increase your Resistance rank. As you rank up, return to camp and complete the next quest. Keep doing this until you reach rank 10.
Pick up the rank 10 quest “The Lady of the Blades”
At rank 10, you’ll gain access to the quest, “The Lady of the Blades.” This quest asks you to take on Castrum Lacus Litore with other players within the Bozjan Southern Front. Castrum Lacus Litore appears at the topmost part of the map as its own separate Critical Engagement. The Castrum will only show up at random times. You must be in the Bozjan Southern Front, then join Castrum Lacus Litore as it spawns. Other people should join you if there are enough eligible players in the instance. This isn’t something you want to tackle alone, so make sure to group up when you can. It also doesn’t hurt to have some of your best Lost Actions equipped for the raid.
Alternatively, you can also join shout parties that begin forming once Castrum Lacus Litore appears on the map. If you’re still not having any luck finding groups, search around for Discord servers dedicated to running Castrum Lacus Litore. Many of these servers started with the level 70 Baldesion Arsenal raid during the Stormblood expansion, and they’re still around today. Find a Discord server for your data center and join a pre-made alliance at the advertised time. This is an effective way to get the raid done, as the fights require some coordination and know-how. You will all enter an instance together, wait for Castrum Lacus Litore to pop, and then head inside as a full group.