Core Keeper • Boss Guide
King Slime
Biome: Any Slime Rune HP: Scale-able Last updated: 2026-02-28
How to summon / find
Place a 'Crown' item on any Slime Summoning Rune.
Recommended food focus
Pick one main meal plan that fits this fight, then keep one backup plan (survival or extra damage).
Melee Damage Armor.
Prep checklist
Bring these before you start—this is the fastest “stop dying” layer.
- ✓ Slime Immunity Gear
- ✓ High DPS Melee Weapon
- ✓ Healing Potions
- ✓ Area of Effect weapons
Deadly attacks to dodge
If you learn only 3 things, learn these. They cause most wipes.
Royal Leap
Massive jump that creates a shockwave.
How to dodge: Dash away as he lands.
Slime Rain
Summons many smaller slimes from above.
How to dodge: Keep moving and use AoE attacks.
Core mechanics
Terraria crossover boss. Leaps and summons Royal Slimes every 700 HP lost.
Win strategy
Focus on clearing the Royal Slime adds to avoid being overwhelmed.
Best food for this boss
Pick 1 meal from the primary plan. If you’re dying, switch to the backup plan instead of forcing DPS.
Primary plan
Top pick
Mold Shark + Iron Tail
- • melee damage: +38.6%
- • crit chance: +13%
Tip: avoid overlapping buffs—pick a focused combo.
Top pick
Mold Shark + Emerald Feather Fish
- • melee damage: +38.6%
- • crit chance: +7%
Tip: avoid overlapping buffs—pick a focused combo.
Top pick
Mold Shark + Golden Puffungi
- • melee damage: +38.6%
- • rarity boost: +1 Tier
Tip: avoid overlapping buffs—pick a focused combo.
Top pick
Mold Shark + Starlight Nautilus
- • melee damage: +38.6%
- • rarity boost: +1 Tier
Tip: avoid overlapping buffs—pick a focused combo.
Common mistakes
Read this if you keep failing. It’s usually one of these.
- • Ignoring the adds
- • Getting cornered
- • Lack of slime immunity
Key drops
What you’re actually here for—and what it’s used for.
Royal Gel
Makes slimes non-hostile.
King Slime Crown
Vanity item with minor stats.
Need golden ingredients faster?
Farming by hand slows down progression. Automate golden crops to power your best food buffs.
Related
FAQ
What food should I bring to King Slime?
Bring 1 main plan (damage or survival) plus 1 backup plan. Avoid overlapping buffs—buffs of the same type usually get overwritten by the last meal you eat.
Do food buffs stack in Core Keeper?
Not usually. Buffs of the same type tend to overwrite, so pick a focused combo instead of stacking many similar meals.
How do I farm ingredients faster?
Automate crops. A golden crop farm is the fastest way to remove the cooking grind for endgame buffs.