CookieRun: Crumble Rune Crystal Dungeon Guide — Boss, Rewards & Farming
The Rune Crystal Dungeon from the August 13 update: White Sugar Guardian's stats, how the dungeon works, Rune Crystal rewards and how to farm Sugar Runes efficiently.
The Rune Crystal Dungeon is one of the two new pieces of content in the August 13 update. It is the dedicated source of Rune Crystals, the material used to craft Sugar Runes for your Cookies' stats — which makes this dungeon the long-term answer to the "should I roll Sugar Runes or save them?" question.
How the dungeon works
The Rune Crystal Dungeon is a daily dungeon that starts with the boss fight right away. Instead of clearing a wave of trash before a boss, you face the White Sugar Guardian directly, and clearing it grants Rune Crystals as completion rewards.
White Sugar Guardian — boss stats
According to the game's client data (version 1.1.002), the White Sugar Guardian is a high-HP, high-ATK boss:
| Stat | Value |
|---|---|
| HP | 6,000 |
| ATK | 500 |
| DEF | 100 |
At 6,000 HP and 500 ATK, this is a sustain check: the boss hits hard enough that an under-leveled support collapses, but it has low DEF, so focused damage actually melts it quickly once your team stays alive.
Recommended team for the dungeon
- 1 tank that can survive the Guardian's attacks — a high-DEF tank with a leveled support behind it
- 2-3 damage dealers — because the boss has low DEF, even mid-tier attackers put out real damage
- 1 strong support — the most important slot here; the fight ends when the healer dies
- Active synergies — at least two, with Duration preferred to keep heals and shields up
If you are not sure which Cookies to bring, check your roster in the team builder or browse the tier list for the strongest picks you own.
Why Rune Crystals matter
Sugar Runes are the endgame stat layer for Cookies — they let you push ATK%, DEF, HP or utility stats beyond what gear alone provides. Before this dungeon, Rune Crystals were scarce enough that rolling Sugar Runes felt risky. With a daily source, the plan changes:
- Farm the dungeon daily — Rune Crystals accumulate fast and fund steady rune crafting
- Roll runes for your core team first — ATK% and Skill Haste runes on your main attacker, DEF/HP on your tank
- Don't hoard forever — the daily income means experimenting with runes is no longer a one-way door
Farming tips
- Run the dungeon every day, even if you clear it slowly — the daily reset makes missed days wasteful
- Prioritize the dungeon early in your daily routine while your strongest team is fresh
- If you cannot beat the boss yet, level your support first; the boss's 500 ATK punishes weak healers more than weak damage dealers
Rune Crystal Dungeon FAQ
When was the Rune Crystal Dungeon added? It arrived with the August 13, 2026 update, alongside Cool Mint Cookie and the event lineup.
What does the White Sugar Guardian drop? Clearing the dungeon grants Rune Crystals, which are used to craft Sugar Runes. Exact per-clear amounts scale with the dungeon level.
What is the best team for the Rune Crystal Dungeon? Any team with a tank, a strong support and two damage dealers works. Since the boss has low DEF, focus on survivability first and damage second.
Is the dungeon worth farming every day? Yes — it is currently the only daily source of Rune Crystals, and they directly fund your Sugar Rune crafting.
Does the dungeon have multiple difficulty levels? The daily dungeon scales as you progress; the boss's base stats above are the client data floor.