The secret ending in Deltarune Chapter 3 is hidden behind a series of intense challenges, secret minigames, and powerful items like the Ice Key and Shadow Mantle. This ending is not unlocked through the main storyline but requires careful planning, mastery of the S-rank system, and the courage to face a hidden boss.
In this guide, we’ll walk through everything you need to know to unlock the secret ending, including how to access the S-room, complete each minigame, get all three key items, and prepare for the final fight against the Knight.
What is the Secret Ending in Deltarune Chapter 3?
The secret ending is an alternate conclusion to Chapter 3 that can only be accessed by completing a hidden sequence involving S-rank challenges and three special items. This ending offers additional lore, a secret boss fight with The Knight, and a deeper look into the mystery surrounding Kris and the dark world.
To reach this ending, players must:
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Achieve S-rank in the Tenna game show or buy entry via Point Merchant.
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Complete three secret minigames found in the S-room.
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Collect the Ice Key, Shelter Key, and Shadow Mantle.
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Equip the Shadow Mantle to survive one-hit kill attacks from the final boss.
Only after completing all three minigames and collecting the required items will the path to the Knight become available.
How to Unlock the S-Room in Deltarune Chapter 3
The S-room is where all three secret minigames are located. To access it:
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You must get an S-rank in the Tenna game show, which requires flawless performance.
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Alternatively, pay 1,500 points to the Point Merchant as a workaround.
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Once unlocked, the S-room is located inside the Green Room.
Inside, you’ll find three challenge portals. Each leads to a different minigame that must be completed solo—as Kris only, without Susie or Ralsei.
How to Get the Ice Key
The first minigame rewards the Ice Key, one of the three essential items for the secret ending.
Follow these steps:
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Find a sword at the start of the challenge.
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Defeat all enemies—including fish, flowers, and purple monsters—to gain EXP.
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Reach Level 4, which unlocks a new path.
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Locate the path behind two cactus plants.
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Cut down trees along the new trail.
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At the end, you’ll find a chest containing the Ice Key.
You must reach max level before progressing. If you miss any enemies, the path won’t open.
How to Get the Shelter Key
The second minigame grants you the Shelter Key, used later to unlock a hidden shelter.
Although the exact mechanics are still being explored, this minigame emphasizes puzzle-solving, careful movement, and environmental navigation. Collecting this key is essential for the secret ending sequence to proceed.
How to Get the Shadow Mantle
The final and most important item is the Shadow Mantle.
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The Shadow Mantle is a defensive item that prevents one-hit kills during the final battle.
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This item is required to face the secret boss, The Knight.
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Completing the third minigame unlocks it—be prepared for a tough challenge.
Once you have all three items, you’re ready to approach the final sequence of the chapter.
How to Use the Ice Key and Shelter Key
The Ice Key and Shelter Key unlock hidden areas:
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Ice Key: Opens a frozen area containing lore and items tied to the final path.
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Shelter Key: Unlocks a secluded area tied to the story’s deeper mysteries.
After unlocking both, return to the S-room and interact with the center structure to begin the final sequence. Ensure you equip the Shadow Mantle before proceeding.
Secret Boss: The Knight
The final boss of the secret path is The Knight, a mysterious figure that plays a central role in Deltarune’s overarching lore.
What to Expect:
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Extreme difficulty: Without the Shadow Mantle, you’ll be vulnerable to instant death.
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Fast-paced battle: Expect rapid attacks and unpredictable phases.
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Lore-heavy encounter: Beating The Knight offers a new ending and dialogue that expands on the main story.
This fight is only possible if all items are obtained and you’re wearing the Shadow Mantle.
Tips to Unlock the Secret Ending
To make your journey smoother, consider the following:
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Practice Tenna’s game before going for an S-rank.
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Farm points early so you can pay the Point Merchant if needed.
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Scout the map and remember cactus/tree placements to save time.
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Play cautiously—the solo minigames are unforgiving.
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Equip healing items and optimize Kris’ build for survival.
Completing all three trials not only tests your skills but also unlocks some of the deepest lore in Deltarune Chapter 3.
Final Thoughts
Unlocking the secret ending in Deltarune Chapter 3 is no easy task, but it offers one of the most rewarding experiences in the game. With a combination of perfect S-ranks, clever minigame strategies, and the power of the Ice Key, Shelter Key, and Shadow Mantle, players can access a hidden boss fight and story segment that redefines the chapter’s ending.
If you’re a completionist or just want to see everything this chapter has to offer, following this guide will help you reach that hidden path and face the game’s ultimate challenge.