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DELTARUNE: TOWER DEFENSE  ·  CHAPTER 1
CARDCASTLE
Chapter 1▶ PLAY NOW

The Dark World Beneath the Closet

It begins with a closet. After a school day gone wrong, Kris and Susie find themselves falling into a Dark World hidden beneath the school's supply closet, a realm made entirely of the dark beneath the light.

This Dark World takes the form of a vast, card-themed kingdom ruled by King, a tyrant who seeks to open the Dark Fountain and plunge both worlds into perpetual darkness. His son, Lancer, is brash, mischievous, and secretly kindhearted, and he serves as the first face of opposition the player encounters.

Guided by Ralsei, the Prince of the Dark World, Kris and Susie travel across The Field toward Card Castle. Along the way, Susie slowly transforms from an antagonist into a genuine ally, while Lancer's relationship with the heroes grows complicated.

The chapter ends with a confrontation against King himself, a battle that tests not just power but mercy, the core mechanic of the DELTARUNE combat system. After the battle, the Dark Fountain is sealed, and the heroes return home.

But Kris is not alone at night. Something else is awake inside them.

Chapter 1 in DRTD

Chapter 1 introduces DRTD's core tower defense loop. Players unlock their first units, common Field enemies turned playable through the gacha system, then face escalating waves across two distinct maps.

The chapter teaches resource management through Lancer's erratic attack patterns, teaches boss targeting with the King encounter, and introduces the concept of secret bosses hidden behind specific conditions.

Units from Chapter 1 span the Card Castle aesthetics: spade soldiers, club knights, heart wizards, and diamond archers. Each rarity tier from Common to Legendary has a Chapter 1 representative, making this the most beginner-accessible chapter in the game.

The FieldA long, open path through the Dark World's countryside. Low branching, high unit density. Ideal for AoE tower builds.
Card Castle ApproachA spiraling path leading to King's fortress. Three lanes merge at the gate, requiring multi-target coverage.
Castle InteriorNarrow corridors inside Card Castle. Tight choke points reward single-target burst units.
standard
RudinnDiamond-shaped Dark World soldier. Fast-moving with low HP. Appears in large swarms in the opening waves.
standard
HathyTop-hat wearing entity. Has a chance to summon additional Rudinns when defeated.
standard
JigsawryPuzzle-piece shaped enemy. Splits into two smaller pieces when hit, requiring follow-up damage.
elite
CloverFour-leaf club knight. High defense and a frontal shield that blocks the first 3 hits per wave.
boss
LancerKing's son, self-proclaimed villain. Charges down the center lane on his bicycle. Multiple HP phases; retreats and returns stronger.
boss
KingRuler of Card Castle. Massive HP pool, AoE dark spear attack, and a berserk phase below 30% HP. Final boss of Chapter 1.
SECRET BOSSJevilThe imprisoned court jester, freed only by those who speak to him three times and solve his riddle. Jevil introduces the concept of "chaos": random AoE attacks that ignore lane pathing entirely. He is considered one of the hardest encounters in the game.