Killroys Slaughterhouse is a set of challenges in World 2 which reward you with skulls to buy various items with from the Skull Shop.
While the rewards are nothing game-changing, it’s a nice free bonus to get each week and this guide will go through how it works and what you should be spending your Skulls on.
How Killroy Works
When you enter World 2, you will definitely notice Killroy and his pile of skulls next to the alchemy cauldron.
Once you click on him, you have two options to choose from, Enter Fight or Skull Shop.
The Fight section always has two rooms to complete (you start off with one Room per week, but unlock the other one when you reach World 4), each of which have a randomized class requirement. This means you can only complete that room with the archer, warrior or mage class that the image specifies.
The monsters you must fight are also randomized, but they tend to be World 1 or World 2 mobs, so they are always easy to kill.
No choice!
Once the fight begins, you will see a timer and a kill counter at the top of the screen and your only goal is to get as many kills as possible before the timer runs out.
The actual kill counter doesn’t actually have any effect on rewards, but enemies have a chance to drop skulls on death, which can then be used to buy various items from the Skull Shop.
Sometimes they can also drop Talent Points for your skill tabs, but there seems to be an ambiguous limit on the amount, as they will stop dropping later on.
Once the timer runs out, you get to choose one of three permanent upgrades: +1 second on the timer, extra Talent Point chance or extra Skull drop chance.
Which Upgrades to Choose?
As mentioned above, there are three different upgrades that you get to choose from after each run.
However they are not created equal, as the middle option, Talent Drops, is completely useless and doesn’t really give a noticeable difference in the amount of Talent Points that are dropped after the first level, so just put 1 point into it.
This means you should spread your points around the Timer and Bonus Skulls upgrades.
The timer has no max amount, so you can technically upgrade it forever, but most people don’t like to spend too long in the Rooms just for some skulls, so they stop after around 60 points or so.
The Bonus Skulls upgrade is slightly misleading, as it says +1% per level, but the amount really degrades fast after 20-30 points, so you won’t notice much difference.
This means, towards the end, it won’t make much of a difference which one you upgrade, but upgrading the timer is the best option if you have the patience to wait it out every time.
Best items to buy from the Skull Shop
The Skull Shop has a lot of variety, but some are definitely worth more than others. A lot of the ‘best’ choices depend on what stage you are at in the game and what you need more progress on.
We made a table showcasing the value of each item in the shop and added a reason when or why that item might or might not be worth buying.
| Item | Description | When to buy | Value |
|---|---|---|---|
 Time Candy | 1 Hour Time Candy (45% chance) 2 Hour Time Candy (50% chance) 4 Hour Time Candy (5% chance) | If you need candy for faster progression early on. |  |
 Black Pearl | Gain +20% XP on current Skill if it’s under level 30 | If you need help with Maestro progression. Time Candy also works for this purpose though. |  |
 Holy Pearl | Gain Class EXP | This is never worth it! |  |
 Crystal Mob | Next kill spawns a Crystal Mob | Can be useful for a few quests or leveling up Crystal Cards. This often bugs out and you get nothing! |  |
 Dungeon Loot Dice | Get a single Dice, as you would from a Party Dungeon | Might get a keychain, depending on roll. Not worth it unless you really struggle with Party Dungeons. |  |
 Arcade Balls | Get 6 Arcade Balls | Not worth it, as you get Arcade Balls passively anyway. | |
 Library Checkouts | Get 2 Library Checkouts | Arguably the best item to buy, unless you somehow already maxed out your talents. |  |
 Refinery Cycle | Completes 1 Refinery Cycle | Good if you need Salts for crafting or have leftover Skulls to use. | |
 Pet Eggs | Get 2 Pet Eggs | Expensive, but good source of Eggs if you need fast pet progression or upgrade materials. | |
 Cooking Ladles | Get 3 Cooking Ladles | Can help very early on to speed up cooking, but later on it’s not worth it. | |
The Library Checkouts also help you reach the World 3 Achievement called Checkout Takeout which requires you to checkout 1,000 talent books from the Library, but it is extremely useful as it gives +5 Max Level to all books and +30% faster library charge rate.
However, if you haven’t reached World 5 and Sailing yet, your book Max Levels will increase greatly from there, so you will need to max out more talents again, so you might want to wait until then and spend the Skulls on World 4 boosts meanwhile.
The Refinery Cycle is always useful as most important crafting recipes need Salts and they can be very slow to gain before you have leveled your Refinery up.
Finally, when it comes to Cooking Ladles, they will help out with cooking early recipes, but once you get high Cooking Efficiency later in the game, you will easily get hundreds of ladles per day on a Warrior class.
Spending Gems to wake up Killroy
It is possible to spend 300 Gems to wake up Killroy once a week, so you get 2 extra rooms to play through for that week, also meaning 2 extra upgrades and more Skulls.
When you reset Killroy, the rooms are not randomized, they’re simply reset.
However, 300 Gems is a steep price for just a few Skulls and there are certainly better things to spend them on in the Gem Shop, so unless you’re a high spender and have everything unlocked from the Gem Shop already, don’t bother.
Especially don’t do it if you don’t have 2 Rooms unlocked yet, aka you haven’t reached World 4 yet.