裏ボス
強い相手を また倒せたら シャドウジェムが もっと 手に入るかも しれないねえ。
ま がんばることだよ！ 一筋縄じゃ いかないだろうけどね…
だけど そのぶん ちゃあんと 見返りがあるはずさ！ヌイ, チャプター2
裏ボス[note 2] はDeltarune（デルタルーン）のボス敵の一種である。これらは任意の、しばしば隠されているバトルであり、そのチャプターの他の部分よりも難易度が高いが、クリアするとパーティに強力な限定装備と、特別なアイテム「シャドウジェム」が1つ報酬として与えられる。
Deltaruneの各チャプターには、裏ボスが1体ずつ存在する。ボスとの戦闘自体は任意だが、ボスには必ず遭遇する。ジェビルを除くすべての裏ボスは、それぞれのチャプターのストーリーを進める上で必ず遭遇する必要がある。ボスとの戦闘にたどり着くには、以前訪れたエリアに戻るサイドクエストをこなす必要がある。戦闘自体は任意だが、裏ボスと出会うすることで、隠された背景、語られていない要素、あるいはDeltaruneのストーリーに関する独自の洞察が明らかになる。
一行のシャドウジェムの管理を担当する店主のヌイは、裏ボスたちの存在を認識しているようで、今後の遭遇をほのめかし、その力について一行に警告する。[6][7][8]
裏ボスとの戦いは台本が用意されており、戦闘の終わりに向けて特定のしきい値に達するまで、決められた攻撃順序と対話が行われる。上記のしきい値に達すると、ボスはより長く、より難しく、より視覚的に精巧な「最終」攻撃を使用し、回避不可能に見えるものの、タマシイに当たる前に終了する「フェイクアウト」攻撃で終了する。こうどうまたはたたかうを通じて裏ボスを倒すと、パーティに特別な装備が与えられる。裏ボスは全員ぶきを提供するが、ジェビルとスパムトンNEOは平和的に倒された場合、代わりに防具を提供する。さらに、ボスのシャドウジェムも与えられる。これはまだ用途が不明な特別なだいじなものである。
ゲームの仕組み以外にも、裏ボスたちは、それぞれは無関係であるにもかかわらず、いくつかのテーマや物語上の要素が共通している。：
- 専用ボイスを持っているが、会話アイコンは無い。
- 戦闘テーマには共通のライトモチーフが含まれている。
- 戦闘ナレーションには「あたりの空気に 自由が満ちる。」という特定のフレーズ、あるいはそのバリエーションが含まれる。
- 会話の中でナイトについて直接言及する。[9][10][11][12]
- 今後のチャプターに登場するキャラクターや出来事を予言する。[13][14][15][16]
- 過去に正体不明の人物と接触していたことを示唆する描写がある。裏ボスたちが全員同じ人物と接触していたかどうかは不明である。[17][18][19]
チャプター3の裏ボスであるナイトは、これらの傾向の大半に例外的に当てはまる。チャプター3をクリアするにはナイトとの遭遇が必須だが、敗北してもストーリーは進行する。ナイトの複雑な攻撃パターンと高いダメージにより数ターンで決着がつくため、単なる負けイベントではなく実際は勝てること自体が「秘密」と言えるだろう。裏ボスに関連する様々なテーマ要素は、代わりにソードルートという大規模なサイドクエストに集約されており、このクエストをクリアすると、ナイトのボス戦の難易度を下げるアイテムであるシャドウマントをKrisは入手する。
チャプター順にリストを記載する。
The former court jester of Card Castle, and Chapter 1's Shadow Crystal boss. He went mad after meeting a "strange someone", which led him to start seeing the world as a game. Thus, he was imprisoned at the ?????? floor. The party can assemble the Door Key to his cell to enter it and fight him.
Reward: Jevilstail (ACTing) or Devilsknife (FIGHTing)
The upgraded form of Spamton, a disgraced spambot salesman found in Chapter 2's Cyber City as a miniboss. After completing his mandatory encounter peacefully, he gives Kris a series of instructions to smuggle him into the basement of Queen's Mansion. Once there, he combines with a machine found in the basement to become Spamton NEO, and attempts to utilize its power to steal Kris's SOUL.
On the Weird Route, he is instead the Chapter's mandatory final boss, having snuck into Queen's Mansion as a result of Kris and Noelle's actions. He still yields a Shadow Crystal upon defeat.
Reward: Dealmaker (ACTing) or PuppetScarf (FIGHTing)
The Roaring Knight is the main antagonist of Deltarune, a mysterious being responsible for the creation of the Dark Fountains. As described above, the Knight serves as the highly unconventional Shadow Crystal boss of Chapter 3, attacking Tenna after his defeat and taking his place as the Chapter's real final boss. Its fight is extremely difficult, although it can be made easier by obtaining the Shadow Mantle earlier in the Chapter. Either winning or losing the fight is a valid end to the Chapter; winning the battle causes the Knight to retaliate and knock the party out anyway.
Reward: BlackShard
The Old Man is a Darkner created from mementos of his Lightner counterpart, Gerson. Making his appearance in Chapter 4, he guides the party and serves as a mentor to Susie, in addition to acting as a shopkeeper. The party can embark on a sidequest to reveal a hidden room in his Study. Inside, the Old Man, as the Hammer of Justice, offers to fight Susie one-on-one in exchange for an expensive weapon.
Reward: JusticeAxe
- ↑ Ura (裏) is Japanese for secret or hidden.
- ↑ Shadow Crystal boss is an unofficial name Per community vote on June 12, 2025, this wiki uses this name, as opposed to any of their other common names.
- ↑
Jevilishly difficult hidden bosses.
— DELTARUNE on Steam (September 17, 2021.) store.steampowered.com. - ↑
The hidden boss becomes subtly more difficult when angry.
— @UnderTale on Twitter, September 30, 2021. - ↑ The filename of Hammer of Justice is
ch4_extra_boss. - ↑
KID! I'M BUSY BECOMING [God]. GO PLAY [Minecrap] OR SOMETHING!
— Spamton, Weird Route, Chapter 2
IT'S NOT MY JOB TO BE SOME KIDS' [Extra Boss]! - ↑ 5.0 5.1 gml_GlobalScript_scr_save script、行16〜28、Chapter 3MediaWiki:Cite.cssページに内容がありません。
- ↑
If you can defeat more strong adversaries, you may find more Shadow Crystals.
— Seam, if given Jevil's Shadow Crystal, Chapter 2
Try your best! It may be tough, but I'm sure it will be worth it! - ↑
You have collected 2 Shadow Crystals.
— Seam, after being given a second Shadow Crystal, Chapter 2
But don't let down your guard. I feel your next opponent may be... hm.
In reality, it may be impossible to win.
... Unless you use the power of the Shadow Mantle.
Here, it may look like an old scrap of cloth, but...
... eh?
I can't find it. Did someone... take it...?
Hahaha! Well now, there goes your one chance of victory! - ↑
It's strange. By all reasonable means, the strength of your next opponent...
— Seam, after being given a third Shadow Crystal, Chapter 4
Should be enough to already ring the bell on your defeat.
But, for some reason... I can't help but think you may win.
What is this feeling? ... Hope? Hahaha! Whatever it is, it's quite funny! - ↑
YOU'RE FAST, FAST, STRONG, STRONG.
— Jevil upon his defeat via FIGHTing, Chapter 1
BUT THERE ARE YET FASTER, YET STRONGER.
THE HAND OF THE KNIGHT IS DRIFTING FORWARD. - ↑
FROM NOW, A NIGHTMARE WILL AWAKEN IN YOUR HEARTS.
— Jevil upon his defeat via Ralsei's Pacify spell, Chapter 1
IN THE SHADOW OF THE KNIGHT'S HAND... - ↑
SPEAKING OF [[Communion]]
— Spamton, "Knight", Chapter 2
KRIS, DID YOU KNOW THAT THE KNIGHT... - ↑
A figure with a sword flew in that door up there.
— Old Man, Chapter 4 - ↑
SOON, THE "QUEEN" RETURNS, AND HELL'S ROAR BUBBLES FROM THE DEPTHS...
— Jevil upon his defeat via FIGHTing, Chapter 1 - ↑
WE DON'T NEED ANYONE ELSE!!! WE DON'T NEED [[Easels]] or [[CRTs]]!
— Spamton in his shop, Chapter 2
WE DON'T NEED ANY [[Man, Woman, or Child]] [[At Half Price]]!!
WE DON'T NEED [[MIKE]]!!!
... ... Mike...
KRIS!!! DON'T BELIEVE [[Anything You See On TV!]] THE MAN'S A CRIMINAL, I TELL YOU!! A CRIMINAL!! - ↑
Chapter 5, The Field of Pink and Gold.
— Hammer of Justice in battle, Chapter 4
The vast garden is charred in an inferno of jealousy. - ↑
TO [$!$!] ME OVER RIGHT AT THE [Good part]!? WHAT ARE YOU, A [Gameshow Host]!?
— Spamton NEO, Weird Route pre-battle, Chapter 2 - ↑
One day, he met a strange someone... and since then, he began to change.
— Seam about Jevil, Chapter 1
He started saying bizarre things that didn't completely make sense -
But didn't completely not make sense, either. - ↑
He started to get a little desperate.
— Orange Addison in Trash Zone, Chapter 2
I heard he started looking for any way to become more popular.
Somehow, he made the right phone call, and found someone.
Or, was he... found BY someone?
They must have been helping him, because suddenly,
He was on the phone all the time... - ↑
For some reason, I found this weird piece-a glass in my desk.
— Hammer of Justice post-boss fight, Chapter 4
Felt like someone really wanted me to use this thing.
But it didn't interest me, so you can take it.