The final Beast Raid of the year, Key to the Heart, has returned, and this round features the fight against Eternal Sugar. Many players already know how tough this boss can be, but the good news is that a fully free-to-play team can still clear Master mode with the right setup and some manual effort. This guide walks you through the F2P team, how the fight works, and what you need to prepare if you’re aiming for a clean Master run. Also check out our Cookie Run Kingdom Codes Guide for more rewards!
What This Beast Raid Is About
Key to the Heart brings back the showdown with Eternal Sugar, a raid that demands quick reactions, good toppings, and strong healing. The boss hits hard, and some mechanics force you to control your cookies and the cannon manually, making the fight more challenging than most raids.
This guide uses the same team setup from a free-to-play alt account, proving that even with low promotions and limited upgrades, it’s still possible to finish the raid if you know what to do.
F2P Team Setup for Master Mode
Below are the cookies, treasures, and topping builds used to clear the raid as a free-to-play player.
Main Team (Phase 1)
Cookies:
- Eternal Sugar
- Pure Vanilla (Awakened)
- Black Sapphire
- Marshmallow Bunny
- Cream Ferret
Treasures:
- Unyielding Berry Necklace (very important)
- Jelly Watch
- Starlight Crown
Toppings Overview
Eternal Sugar
- Full Raspberry
- Focus on Poison Damage if possible
- No need for Damage Resist
Black Sapphire
- Full HP
- Poison Damage if available
- Black Sapphire may only cast once before dying, and that’s fine
Pure Vanilla Awakened
- Full HP
- Optional: cooldown or a little damage resist if you can roll it
Cream Ferret
- Raspberry + Swift Chocolate mix
- Cooldown and Attack/Crit help the healing
Marshmallow Bunny
- Full Swift Chocolate
- High cooldown and amplify buff are ideal
Steel Phase Team (Phase 2)
Cookies:
- Hollyberry (Awakened)
- Silent Salt
- Lindser
- Mystic Flower
- Sugarfly
Treasures:
- Old Pilgrim’s Scroll
- Whistle
- Vial
Toppings Overview
Hollyberry Awakened
- Full Raspberry
- Steel damage substats help a lot
Silent Salt
- Full Raspberry
- Boosting steel damage makes a big difference
Lindser
- HP + cooldown is ideal
- Attack speed biscuit helps
- On a low-promo F2P account, expect Linds to die early
Mystic Flower
- Full Swift Chocolate
- Keep cooldown priority high for constant healing
Sugarfly
- Full Peanut
- HP is needed to survive
How to Run the Fight
1. Turn on Auto
Because the berry necklace treasure needs to trigger on cooldown, automatic mode is required.
2. Skip the First Cannon Section
If you’ve cleared the raid before, you can skip the cannon scene and jump right into combat.
3. Watch the Boss HP Drop
During the steel phase, Eternal Sugar triggers a move that drops its own HP briefly.
After this animation, immediately switch to the Steel Team.
This timing is important—switch too early or too late and your damage rotation becomes inconsistent.
4. Expect Some Cookies to Die
This is normal on a low-stat F2P account.
Black Sapphire and Linds often die quick, but the run is still clearable.
5. Final Cannon Phase (Manual)
You will control:
- 10 cookie buttons (1–0 keys)
- The cannon (– key on keyboard)
Switch to:
- Auto ON
- Slow speed
This lets you react to charm faster. When charm hits, spam the keys to wake your cookies before they die.
This part is messy, but even with fewer survivors, it’s still manageable if you stay on the buttons.
Why HP Toppings Matter
Unlike other raids where damage resist is king, Eternal Sugar hits too hard and too often, making HP the better choice.
More HP means:
- Your healers get more value
- Poison dealers survive long enough to cast
- You avoid one-shot deaths
This is especially true on emulator, where button timing is harder than touchscreen play.
Key to the Heart’s Master raid is one of the most stressful fights in Cookie Run Kingdom, especially with all the button-mashing and charm mechanics. But with a proper free-to-play setup, smart topping choices, and correct timing, clearing this raid is absolutely possible. Stay patient, keep your cookies tanky, and practice the swap timing—and you’ll secure your Master clear without needing premium units. Good luck claiming those Beast Raid rewards.