When your castle is attacked in Crowfall, you have a few options. You could, for example, sit back and cry a bunch. That’s time-honored, but it’s also unlikely to stop the attack. You could also try insulting the attackers instead. Or you could build a ballista atop your parapets and start fighting back against both players and siege machinery. That’s probably the best option if you would like to actually retain your castle.
Players can build a ballista simply by going to one of the appropriate ballista pads and building one via the crafting interface; more powerful ballistae have a wider selection of powers to deploy on the battlefield. Aside from the basic shots to demolish enemy catapults, you can also deploy healing fields for allies and sparking damage to force enemies to spread out, as well as a temporary shield to absorb some damage when attackers start targeting your static defenses. Check out both the walkthrough and the process of making ballista effects in the videos below.