To pursue broad completion in DELTARUNE Chapter 4, continue from the save you want to keep, recruit every enemy you can, check your recruitment status at the third Sanctuary’s blue judgment bell, explore optional spaces before moving on, and complete the piano puzzle that opens the route to Gerson, the chapter’s secret boss. This guide covers the major completion goals and known reward leads; it is not an independently verified inventory of every item, conversation, or interaction in the chapter.
What counts as 100% completion in Chapter 4?
The game does not define a single public “100%” checklist or percentage for Chapter 4. Players may mean different things by it: recruiting all possible enemies, finding major optional rewards, seeing optional scenes, or locating every item and dialogue variation. The route below focuses on preserving recruits, checking progress, exploring optional content, and completing the secret encounter. The available walkthrough coverage does not establish every possible interaction or collectible as an exhaustive list.
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For recruitment, the official DELTARUNE Gameplay Reminder Cheat Sheet says, “Near the end of a Chapter there will always be a way for you to confirm whether you’ve RECRUITed all the enemies or not.” In Chapter 4, the community-maintained Deltarune Wiki identifies that check as the blue judgment bell in the third Sanctuary.
Start from the save you want to carry forward
If you want Chapter 4’s choices and collected resources to be part of a continuing file, load the intended save slot and continue using its Chapter 3 completion data where available. Toby Fox’s official gameplay reminder says reaching a chapter’s credits creates completion data in the current save slot. Continuing with that data carries collected items, money, equipment, and choices into the next chapter.
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Starting a chapter without completion data is possible, but it uses a default state. That state may omit recruits or activities associated with the file you would otherwise continue. The official reminder also notes that recruits make Castle Town livelier and may unlock activities there.
Recruit enemies instead of making them Lost
Recruitment is the main missable outcome to protect. According to the official gameplay reminder, from Chapter 2 onward, sparing or pacifying enemies can recruit them. Defeating a recruitable enemy violently makes it Lost, preventing its recruitment. Violence can also raise HP, Attack, and Magic for the rest of that chapter, so the choice has a short-term battle benefit and a possible longer-term cost.
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Use nonviolent battle actions
- Raise MERCY, then SPARE. Use ACT options to increase an enemy’s MERCY and spare it once it reaches 100%.
- Make an enemy TIRED, then PACIFY. Where available, use Ralsei’s PACIFY after making the enemy TIRED.
- Check the result at the third Sanctuary. Inspect the blue judgment bell before advancing beyond the point where you can correct recruitment mistakes.
The bell check is a community-wiki report of Chapter 4’s location and function; the official reminder establishes the broader rule that a recruitment check is available near the end of each chapter. Recruiting all possible enemies is worthwhile for Castle Town and later scene variations, but the official reminder describes the story effects of missed recruits or repeated violence as minor.
Explore optional content before leaving an area
Third-party Chapter 4 walkthroughs identify optional conversations and scenes, hidden spaces and chests, an Egg and moss, donation-linked rewards, and an optional dog-climbing encounter. These are useful leads, not a verified exhaustive catalog. Treat each area as a sweep rather than assuming that the main route reveals everything.
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- Check side paths, rooms that look out of the way, and objects that invite interaction.
- Talk to optional NPCs before story transitions; some conversations or scenes may not be available afterward.
- Look for hidden rooms and chests in the town and Dark World areas described by walkthroughs.
- Watch for the chapter’s Egg and moss, as well as the optional dog-climbing encounter.
- Consider donation-linked rewards before spending or leaving the relevant area.
One walkthrough reports that donating at least 9,999 Dark Dollars earns Gold Widow armor. This is a third-party guide claim, not an official published statistic; confirm the amount and reward in your current game before treating it as a definitive requirement.
Unlock and defeat Gerson, the Hammer of Justice
Gerson, also called the Hammer of Justice, is Chapter 4’s optional secret boss. Third-party guides report that defeating him awards Susie the Justice Axe and gives the party a Shadow Crystal. The route requires a puzzle detour, and the encounter is a Susie solo survival fight.
Open the fireplace passage
- Progress until you obtain the Claimb Claws.
- Return to Gerson’s study and climb the nearby stack of books to reach the golden piano.
- Play the reported sequence: up, dot, up, left, down, dot, right, dot, right, down, left, dot.
- Enter the passage opened in Gerson’s fireplace.
Deltia’s Gaming and Pocket Tactics describe this piano route, but the note transcription is guide-reported rather than an official published puzzle solution. If the sequence does not work, recheck the piano’s visual note prompts and the guide’s notation against what the game displays instead of assuming the puzzle has a second solution.
Survive the fight
Pocket Tactics describes the encounter as a solo fight in which Susie uses her axe to deflect incoming arrows. Its guide calls out diagonal attacks, a bouncing shell, hammer volleys, and slashes; heal when needed and adapt to the pattern rather than relying on an unsupported fixed turn count. Deltia’s Gaming describes a green-heart defensive mode and says the encounter concludes through blocking and dodging as the story conversation finishes.
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Collect the reward without overreading it
The reported rewards are the Justice Axe for Susie and a Shadow Crystal. Pocket Tactics reports that the axe raises Susie’s Attack by 12, while Deltia’s Gaming quotes its description as: “It has no special powers. However, in order to attain this item, you became much stronger.” Those are guide-reported item details, not independently verified current stats. The sources do not establish that collecting the Shadow Crystal unlocks a secret ending; treat that claim as speculation, not a confirmed reward effect.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Recover earlier secret-boss rewards in Castle Town
If you defeated a Shadow Crystal boss earlier in the same save slot but do not have that boss’s crystal or associated equipment in the file you are using, the community-maintained Deltarune Wiki reports that these rewards can be collected at the west-side cliff in Castle Town. Its account says this recovery does not require continuing from the completion data that recorded the boss victory.
Final Chapter 4 sweep before the credits
Use this as a practical checkpoint before finishing the chapter. It covers the major goals supported by the official reminder and available walkthrough leads, not every possible definition of 100%.
- Save continuity: You are playing the intended save slot and have continued from its completion data if carrying forward its items, money, equipment, and choices matters to you.
- Recruitment: You used SPARE or PACIFY routes for recruitable enemies and checked the blue judgment bell in the third Sanctuary.
- Optional exploration: You searched side paths and hidden spaces, opened chests, spoke to optional NPCs, and checked for the Egg, moss, dog-climbing encounter, and donation rewards.
- Secret encounter: You opened the fireplace passage, fought Gerson, and collected the available rewards if you want Chapter 4’s optional boss content.
If you want a literal all-items, all-dialogue, or all-variation completion record, the checklist above cannot certify it: the cited guides do not provide an independently verified, exhaustive audit of every Chapter 4 interaction.
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