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Most Core Keeper bosses do not return on an automatic timer. To fight one again, go back to its original rune or arena and use that boss’s designated summon item. Runes cannot be destroyed, but the valid summon item is consumed when the spawn starts. The exception to ordinary rune placement is important: Omoroth is called by fishing with an Expert Lure, while Druidra, Crydra, and Pyrdra are roaming titans summoned with their matching wind organs near their tracked locations.
Use the reference table below to identify the exact item, location, source, and any documented waiting condition. A summon item for one boss or rune will not substitute for another.
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How boss respawning works
After a defeat, return to the place where that boss was originally summoned. Fixed bosses use an indestructible rune or a defined arena point. Put the correct item on that rune, place it in the specified arena, or use the boss-specific interaction. The item is normally consumed as the summon begins, so verify the location before confirming the placement.
- Travel to the boss’s original arena, rune, throne room, dungeon rune, or roaming-titan area.
- Check that the previous fight’s soul or other post-fight state has cleared.
- Equip or select the exact summon item listed for that boss.
- Place the item on the rune or arena point, or perform the required fishing or wind-organ interaction.
- Move clear of the spawn area and wait for the boss to materialize.
If nothing happens, do not throw another item down immediately. The most common causes are a mismatched rune, an incorrect item, or a boss-specific cooldown still in progress.
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Understanding runes and summon interactions
Runes are permanent, indestructible ground objects. They are not decorative markers and cannot be moved to a more convenient base location. Each one is linked to a particular encounter, so the rune itself determines which boss appears when a compatible item is placed on it. This is why a Giant Slime Summoning Idol can call four different bosses without being a universal key: the Glurch, Ivy, Morpha, or Igneous rune tells the game which one to create.
There are four practical summon patterns in this guide:
- Rune placement: Put the listed idol or item directly on a fixed boss rune or rune circle.
- Arena placement: Place an item at a defined arena point, as with Azeos or Ra-Akar.
- Fishing: Equip the Expert Lure in your off-hand and cast into Omoroth’s whirlpool.
- Roaming-organ use: Activate the matching wind organ near the currently tracked location of Druidra, Crydra, or Pyrdra.
Knowing the interaction type prevents wasted items. An idol dropped beside a whirlpool does nothing, and a wind organ used at a fixed rune is not a substitute for that rune’s summon item.
Complete boss respawn reference
| Boss | Summon interaction | Required item or condition | Location | Documented timing or special rule |
|---|---|---|---|---|
| Glurch the Abominous Mass | Place the item on the rune | Giant Slime Summoning Idol | Glurch’s slime rune | Uses the normal rune interaction |
| King Slime | Place the item on the rune | Crown Summoning Idol | Slime summoning rune | Not interchangeable with the Giant Slime Summoning Idol |
| Ghorm the Devourer | Place the item on the rune circle | Ghorm Summoning Idol | Ghorm’s rune circle | Uses the normal rune interaction |
| The Hive Mother | Place the item on the rune circle | Hive Mother Summoning Idol | Hive Mother rune circle | Uses the normal rune interaction |
| Malugaz the Corrupted | Place the item at the sigil | Skull of the Corrupted Shaman | Throne room sigil | Crafted from three Crystal Skull Shards |
| Azeos the Sky Titan | Place the item in the arena | Large Shiny Glimmering Object | Azeos’s arena | After a kill, allow about five minutes for the soul to disappear and about 20 seconds for the shadow to return; the documented total is about 5 minutes 20 seconds |
| Ivy the Poisonous Mass | Place the item on the rune | Giant Slime Summoning Idol | Ivy’s rune circle | Shares the Giant Slime idol with other slime bosses |
| Omoroth the Sea Titan | Fish at the arena whirlpool | Expert Lure, equipped in the off-hand | Omoroth’s arena whirlpool | A five-minute-or-longer soul-disappearance delay may apply |
| Morpha the Aquatic Mass | Place the item on the rune | Giant Slime Summoning Idol | Morpha’s rune circle | Shares the Giant Slime idol with other slime bosses |
| Igneous the Molten Mass | Place the item on the rune | Giant Slime Summoning Idol | Igneous’s rune circle | Shares the Giant Slime idol with other slime bosses |
| Ra-Akar the Sand Titan | Place the item in the arena | Thumper | Ra-Akar’s arena | Uses an arena placement rather than a standard rune circle |
| Druidra the Wild Titan | Use the organ near the tracked titan | Wind Organ of Wilderness | Near Druidra’s roaming location | There is no single permanent rune to revisit |
| Crydra the Ice Titan | Use the organ near the tracked titan | Wind Organ of Ice | Near Crydra’s roaming location | There is no single permanent rune to revisit |
| Pyrdra the Fire Titan | Use the organ near the tracked titan | Wind Organ of Fire | Near Pyrdra’s roaming location | There is no single permanent rune to revisit |
| Core Commander | Place the idol on the rune | Core Commander Summoning Idol | Rune inside the Crystal Meteor | First activation also requires all six titan souls and shattering the meteor |
| Nimruza, Queen of the Burrowed Sands | Place the item on the rune | Corrupted Sap | Rune in Nimruza’s Oasis dungeon | Uses her dedicated dungeon rune |
Rune-based bosses
Glurch the Abominous Mass
Return to Glurch’s slime rune with a Giant Slime Summoning Idol. Place the idol directly on the rune. The same item is also used for Ivy, Morpha, and Igneous, so the rune identifies which boss will spawn.
King Slime
King Slime uses a Crown Summoning Idol on a slime summoning rune. Do not use a Giant Slime Summoning Idol here; the two items are different even though both encounters involve slime.
Ghorm the Devourer
At Ghorm’s rune circle, place a Ghorm Summoning Idol. The circle is the required interaction point, not any convenient location along Ghorm’s tunnel.
The Hive Mother
Take a Hive Mother Summoning Idol to the Hive Mother rune circle and place it there. If the item is not accepted, recheck that you are at the original circle rather than another nearby hive chamber.
Malugaz the Corrupted
Malugaz is summoned at the sigil in the throne room. Use a Skull of the Corrupted Shaman at that sigil. Each skull is crafted from three Crystal Skull Shards, so collect enough shards before returning if you plan repeated attempts.
Ivy the Poisonous Mass
Ivy’s rune circle accepts a Giant Slime Summoning Idol. The idol is not Ivy-specific: it also calls Glurch, Morpha, or Igneous when used at those bosses’ own circles.
Morpha the Aquatic Mass
Place a Giant Slime Summoning Idol on Morpha’s rune circle. The arena and rune must belong to Morpha; carrying the idol to another slime boss’s location changes the result.
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Igneous also uses the Giant Slime Summoning Idol, placed on Igneous’s rune circle. Confirm the circle before consuming the idol, especially in areas where several slime arenas are close together.
Arena-placement bosses
Azeos the Sky Titan
Put a Large Shiny Glimmering Object in Azeos’s arena. Azeos has a visible post-fight state: the soul generally takes about five minutes to disappear, followed by about 20 seconds before the shadow returns. The documented immediate-respawn timing is therefore approximately five minutes and 20 seconds after the fight. If the object is already placed, the titan can appear as soon as that state is ready.
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For repeat runs, the useful distinction is between placing the object and the arena becoming available. You can prepare the arena and then wait, but placing another object before the prior state clears is not a way to shorten the interval. If the shadow has not returned, treat the encounter as still resolving.
Ra-Akar the Sand Titan
Use a Thumper in Ra-Akar’s arena. This is an arena placement interaction rather than a conventional rune-circle idol, so stand at the arena point and place the Thumper there.
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Core Commander’s summon point is the rune inside the Crystal Meteor. Once the encounter has been unlocked, place a Core Commander Summoning Idol on that rune. The first activation has additional progression requirements: obtain all six titan souls and shatter the meteor. Later defeats can be followed by placing another idol on the same internal rune.
That progression check is separate from ordinary respawn timing. If the meteor has not been shattered or the six souls are incomplete, the first summon cannot begin even when you are carrying the correct idol and standing on the correct rune. Complete those one-time requirements before spending an idol.
Nimruza, Queen of the Burrowed Sands
In Nimruza’s Oasis dungeon, place Corrupted Sap on the dungeon’s rune. This dedicated item and location are separate from the titan organs and the slime idols.
Omoroth: the fishing respawn
Omoroth does not use an idol-on-rune interaction. Equip an Expert Lure in your off-hand, go to the arena whirlpool, cast with a fishing rod, and reel in the bite. The lure is the summon item; placing it on the ground will not start the encounter.
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Use the arena whirlpool rather than an ordinary fishing location. A correct rod and lure used outside the boss arena can look identical to a failed summon, so confirm both the off-hand slot and the exact whirlpool before casting repeatedly.
Roaming titan respawns
Druidra, Crydra, and Pyrdra are roaming titans, so searching for a fixed rune is the wrong approach. Track the titan’s current location, travel near it, and use the matching wind organ:
- Druidra: Wind Organ of Wilderness.
- Crydra: Wind Organ of Ice.
- Pyrdra: Wind Organ of Fire.
Use the organ near the tracked location, not near a previous fight or an unrelated titan. A correct organ at the wrong roaming location can look like a failed summon. Their summon method is therefore different from both fixed rune bosses and arena titans: the tracked position is part of the requirement.
Where to obtain summon items
Cloaked Merchant stock
The Cloaked Merchant sells several boss idols, including the Giant Slime Summoning Idol for 200 Ancient Coins. Merchant inventory is not permanently fixed: stock restocks after time passes, so check again if the idol is absent. Because one Giant Slime idol serves four different bosses, buy enough for the number of encounters you intend to run.
The 200-coin price applies to the Giant Slime Summoning Idol, not automatically to every summon item in the game. Keep the item name and price distinct when budgeting a rematch session. If the merchant does not show the idol on the first visit, waiting for a restock is more useful than searching unrelated vendors.
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Ancient Shrine and Spirit Merchant sources
Titan summon items can be crafted at the Ancient Shrine or obtained through the Spirit Merchant associated with the Ancient Hologram Pod. The exact route depends on the item and the world version, so use the recipe or merchant listing available in your current save rather than assuming every titan uses the same source.
This matters most for late-game planning: Druidra, Crydra, Pyrdra, Azeos, Omoroth, and Ra-Akar do not share one universal consumable. Check the item’s exact name before leaving the base, then bring it to the interaction listed in the table.
Crafting Malugaz’s skull
The Skull of the Corrupted Shaman requires three Crystal Skull Shards. Gather the three shards, craft the skull, and take it to the throne-room sigil; shards alone cannot be placed to summon Malugaz.
Why a summon item does nothing
Wrong interaction point
Check the boss table first. A rune, rune circle, throne-room sigil, arena point, whirlpool, and roaming-titan location are different interactions. Moving only a few tiles can matter when an arena has a defined placement spot.
Wrong item
Boss items are not generic keys. The Crown Summoning Idol does not replace a Giant Slime Summoning Idol, and a wind organ cannot replace an arena item. For slime bosses, the same Giant Slime idol works only because each boss has its own compatible rune.
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Post-fight state has not cleared
Azeos and Omoroth have documented soul-related delays. Wait for the relevant state to disappear before placing another item or casting again. Other bosses can also fail to respond while their encounter state is still resolving.
First-time progression is incomplete
Core Commander’s first activation requires all six titan souls and the Crystal Meteor to be shattered. If those conditions are not met, placing the idol cannot begin the normal repeat-summon cycle.
Item was consumed but the fight is not visible
Move away from the spawn point, check the arena perimeter, and allow time for the spawn animation. For Omoroth, verify that the Expert Lure is in the off-hand and that the cast landed in an arena whirlpool; an ordinary fishing spot will not trigger the boss.
Similar arenas caused a mix-up
Several slime encounters use the same idol, which makes it easy to remember the item but forget the destination. The idol does not choose a boss from your inventory. Glurch’s, Ivy’s, Morpha’s, and Igneous’s individual runes determine the result. Likewise, a slime rune cannot be used for King Slime, whose Crown Summoning Idol is separate.
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Efficient repeat-fight checklist
- Write down the boss and the exact item before leaving your base.
- Carry spare healing, armor, weapons, and an escape route; the summon item may be consumed immediately.
- For rune bosses, use the original rune rather than recreating an arena elsewhere.
- For Azeos and Omoroth, account for the soul-related wait before scheduling another attempt.
- For roaming titans, bring the organ that matches the titan’s element or environment and confirm the tracked location.
- For Core Commander, verify the one-time meteor and titan-soul requirements before spending an idol.
- Keep summon items in separate labeled storage so similar idols are not confused.
- For Malugaz, carry a complete Skull of the Corrupted Shaman; three loose shards are not a substitute.
- For Omoroth, put the Expert Lure in the off-hand before reaching the whirlpool so the fishing attempt is ready.
- For merchant-bought idols, carry enough Ancient Coins and remember that stock can require time to restock.
Quick decision guide
If you see an indestructible rune, identify the boss tied to that rune and place its listed item. If you are at a whirlpool, fish with an Expert Lure for Omoroth. If the boss moves around the world, use the matching wind organ near its tracked position. If you are inside the Crystal Meteor or Nimruza’s Oasis dungeon, use the dedicated item shown in the table. This approach resolves nearly every failed-respawn case without wasting another summon item.
Respawn method comparison
| Method | Bosses | What determines the target | Main failure to avoid |
|---|---|---|---|
| Fixed rune or rune circle | Glurch, King Slime, Ghorm, Hive Mother, Ivy, Morpha, Igneous, Malugaz, Core Commander, Nimruza | The specific rune, circle, or sigil | Using a similar-looking item or standing at the wrong permanent marker |
| Arena placement | Azeos and Ra-Akar | The defined arena point | Placing the item outside the arena or ignoring a post-fight state |
| Fishing interaction | Omoroth | The arena whirlpool, Expert Lure, and fishing rod | Using an ordinary fishing spot or forgetting the off-hand lure |
| Roaming organ | Druidra, Crydra, Pyrdra | The titan’s tracked current location and matching organ | Searching for a permanent rune or using the organ far from the titan |
This comparison is useful when a summon appears to fail. First identify which method the boss uses, then verify every part of that method: target marker, item, and any wait or progression requirement. It is faster than repeatedly trying different items at the same location.
Timing and resource planning
Most rune encounters can be attempted again once the correct item and location are available, but the game does not supply one universal respawn timer for every boss. The documented waits in this guide are encounter-specific. Azeos takes about five minutes for the soul to disappear and about 20 seconds for the shadow to return, for roughly 5 minutes 20 seconds total. Omoroth may require five minutes or longer for its soul state to disappear. Treat these as practical minimum waits, not a promise that every world or version will behave identically.
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Resource planning is similarly boss-specific. A single Giant Slime Summoning Idol supports four separate slime bosses, but each attempt consumes one idol at the chosen rune. Malugaz needs three Crystal Skull Shards per crafted skull. The Giant Slime idol costs 200 Ancient Coins from the Cloaked Merchant when stocked, and titan items may instead come from the Ancient Shrine or the Spirit Merchant. Keeping a small reserve prevents a long trip from ending after one failed attempt.
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Frequently Asked Questions
Do Core Keeper bosses respawn automatically?
Usually not. Return to the original rune or arena and use the boss-specific summon item. Omoroth requires fishing with an Expert Lure, and the three roaming titans require matching wind organs near their tracked locations.
Where do I put a boss idol?
Place it on the boss’s own indestructible rune or rune circle unless the table specifies an arena point, throne-room sigil, or another interaction. A summon item for one rune will not work on another.
Can one Giant Slime Summoning Idol summon several bosses?
Yes. The Giant Slime Summoning Idol is used for Glurch, Ivy, Morpha, and Igneous. You must take it to the correct boss’s rune; the idol itself does not select the boss.
Why does King Slime not spawn with a Giant Slime Summoning Idol?
King Slime uses a Crown Summoning Idol on a slime summoning rune. It is a different item from the Giant Slime Summoning Idol.
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Equip an Expert Lure in your off-hand, go to Omoroth’s arena whirlpool, cast with a fishing rod, and reel in the bite. A five-minute-or-longer soul-disappearance delay may apply after a defeat.
How long must I wait to respawn Azeos?
Allow about five minutes for Azeos’s soul to disappear and about 20 seconds for the shadow to return, or roughly 5 minutes 20 seconds in total. If the Large Shiny Glimmering Object is already placed, Azeos can appear as soon as the state is ready.
Where do I summon Druidra, Crydra, and Pyrdra?
They do not use one permanent rune. Track the titan, travel near its current location, and use the matching Wind Organ of Wilderness, Wind Organ of Ice, or Wind Organ of Fire.
What is required for the first Core Commander summon?
You need all six titan souls and must shatter the Crystal Meteor. After that first activation, place a Core Commander Summoning Idol on the rune inside the meteor for later fights.
How much does the Giant Slime Summoning Idol cost?
The Cloaked Merchant sells it for 200 Ancient Coins when it is in stock. The merchant restocks after time passes, so check again if it is unavailable.
The Bottom Line
To respawn a Core Keeper boss, use its exact summon item at its exact rune, arena, whirlpool, sigil, or tracked roaming location. Giant Slime idols cover four slime bosses, King Slime has a Crown idol, Omoroth requires Expert Lure fishing, and the roaming titans require matching wind organs. Wait for Azeos or Omoroth’s post-fight soul state, and complete Core Commander’s one-time progression requirements before spending another summon item.
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