How to Defeat the Sirena

Chapter 8 of Cataclismo is home to beefy boss Sirena. As if the Sirena being a formidable foe weren't enough, you're also challenged to defend locations outside of your base too. Here’s how to beat the Sirena in Chapter 8.

Resource Preparation

Before you get to the area you’ll be tasked with defending, you’ll have to navigate your way through the forest to gather wood and stone pieces, with stone being the most important to gather. Luckily all available stone will be directly in your path going to the defense location.

You won’t be able to harvest more resources in this mission, so it’s worth recycling items you place down on the way to the stronghold, giving you more to work with when the time comes to prepare your defenses.

Building Defenses

You’ll have just around half a day to make your defenses for this boss fight. Remember to pause when you build since building is instant even if your game is not progressing. Your goal is to protect a Stronghold with various military units you found in the forest.

The Sirena has a few different attacks that can break down your structures quite easily in just one or two hits. The first is a ranged attack where it launches a ball made of flesh and other nasty things. The second is a sweeping 360 attack that will devastate the immediate area around it.

Both of these attacks can deal around 78 blocks of damage. This is estimated from the radius of one circle of damage being around 5 blocks. So planning ahead is key here.

The placements Sirena can appear from vary but we’ve found that it would mostly focus on the middle hole since that’s directly in front of your Stronghold. Sirena doesn’t focus on staying outside of the main middle area for too long so be sure to build your heavier defenses near your Stronghold.

Aside from the high damage attacks the Sirena does itself, every time it spawns in a new hole, a giant wave of Vermin will spawn. Vermin are the smaller, more easily killed enemy type but a whole army of them spawning in every few seconds can be a lot to manage.

With all this being said, do not build anything directly around the holes the Sirena spawns from. Instead, focus on fortifying your walls just a few blocks away from the holes the Sirena will spawn from. If you position your walls to be JUST out of reach from the sweeping attacks, you have a greater chance of keeping your core walls up. You should also consider building your walls 10 blocks high to get the max bonus to help your survival chances.

You’ll want the heaviest and biggest wall around your Stronghold since it’s incredibly easy for the Vermin to get through the walls and hit the main building. Build a wall at least 4 to 5 blocks high (the higher the better though!) and add all the defensive and damage bonuses you can with the Windows and Banners. Build two walls around the main hole the Sirena will appear from (the one in front of the Stronghold) and ensure they are reinforced with decent elevation and with all the damage and ranged bonuses from Banners and Windows.

Be sure to add various stairs for your troops to escape from since you’ll have to actively move them around to avoid taking most of the damage. Next, build the surrounding walls to the North and East at the holes where the Sirena will appear from. Make them fairly sturdy, about 3-4 blocks high, so that the Vermin get distracted to take down those walls first while your troops can rain down arrows and cannon fire at them to thin out the crowd hitting the main walls behind the fake ones.

These walls are bound to be broken down. There’s no stopping that. So, behind each wall a few blocks behind, make sure you create an additional fall-back point that’s reinforced to a minor degree. We chose to make two separate fall-back points that would give our troops the best angle on the center hole. Even if you choose to make a smaller retreat point, make sure that it still has Banners and Windows even if it is just one block high.

Add rooftops to each of these walls to ensure your troops maintain their accuracy. Getting wet from rainfall lowers your troops’ aim accuracy. You don’t have to build a full roof, just half a roof covering one block behind the Window will be enough.

Finally, since you’re given a handful of Hunters that deal their best damage 10 blocks or higher up, create a few small tower-like areas in the north, east, and near the stronghold to place a Hunter. Try to position them within reach of two possible holes the Sirena can come out of, but out of range of her 360 degree attack. You may not be able to move the hunters around quickly, but they can be good to leave in place in case she appears at any hole. With any luck she’ll ignore the smaller targets in favor of your other units, allowing them to snipe with little worry.

Fighting the Sirena

This is the first boss where you will need to actively micromanage your troops to avoid the Sirena’s devistating attacks when you see the red indicator on the ground flash. Most of your units can tank one or two direct hits from the Sirena but you’ll have to be extra careful and withdraw your particularly injured units to a safer vantage point.

As soon as a wall your units are stationed at falls, move them back to your fall-back stations or to the main station you created in front of your Stronghold. In this run, we stationed six to seven troops at each front wall. The type of units you have in each group doesn’t matter as long as you separate your Cannoneers and the Hunters to be evenly distributed.

We left one Cannoneer at the top of the main wall in front of the Stronghold to provide back up if any of the troops were in dire need of retreat and needed cover fire. You get a total of 15 military units and you can’t risk losing any of them since every point of damage matters.

Don't forget too that when any of your walls are broken, you can easily pause the fight and build them up again. The best time to do this is when the Sirena disappears after fighting for a bit, especially if it indicates the Serena is moving to an area that's suffered heavy damage. If any of your units are stuck from falling down a wall, take the time to build new stairs for them to regroup.

The damage your units can do when behind proper boosting walls can be incredibly impactful. When you notice the Sirena start to become bloodied, you can focus all damage on the boss and it should die fairly quickly.

You can position your units to better ground but if you end up with a few Bowmen on the ground and direct them to the Sirena at this point, it should be fine since the boss will be at its weakest. Once you’ve taken down the Sirena, you’ll have completed Chapter 8 and succeeded in your first giant boss kill!