The Yellow and Blue fight in Deltarune Chapter 5 isn’t won by stacking damage. Yellow pulls the party into a courtroom-style trial on alternating turns, and the only way to end the encounter is to name the correct culprit and back it up with the matching evidence. Choose wrong, and the duo simply repeats their previous attack until the next trial loops around, which only drags things out.
Quick answer: Solve the four cases in this fixed order — Case 1: Seth + PerpBook, Case 2: Green + YellowShred, Case 3: Aqua + RedSplatter, Case 4: Blue + BlueString. Land Case 4 correctly, and the battle ends.
How the Yellow and Blue trial works
A trial only opens once you have enough TP to run the Justice ACT. Use Kris’ ACT, select Yellow, and the trial option appears. Yellow reads out the crime, then you pick a suspect, followed by the evidence that links them to it. The Justice ACT needs roughly 40% TP to fire, so don’t try to open a trial before the gauge can cover it.
If your TP is too low, spend turns on HelpOut with Susie and Ralsei to build it back up quickly. There are five suspects across the whole fight — Aqua, Seth, Green, Yellow, and Blue — but the cases run in a set order, so the answers below always apply.
All four trial answers (culprit and evidence)
| Case | Culprit | Evidence |
|---|---|---|
| 1. A Floradinn was crushed flat | Seth | PerpBook |
| 2. Yellow’s favorite shirt turned jet black | Green | YellowShred |
| 3. Green’s handkerchief was stolen | Aqua | RedSplatter |
| 4. Yellow’s secret special petals went missing | Blue | BlueString |
Case 1: A Floradinn claims it was flattened. Seth is the culprit, and the PerpBook is the proof, since Seth carries that book everywhere.
Case 2: Yellow reports that his favorite yellow shirt was defaced and blacked out. Accuse Green and present the YellowShred, the torn piece of the shirt.
Case 3: Green reports that his handkerchief was stolen. Aqua is the culprit, and the RedSplatter is the evidence left behind while trying to change the handkerchief’s look. This is the case that usually forces you to request evidence from Blue first.
Case 4: Yellow returns as the victim, now claiming his secret special petals are gone. Name Blue and present the BlueString. Yellow gets angry at the accusation, but Blue confesses. Yellow then tries to punish himself, only for the bullets in his revolver to come out as blue flowers, and he calls off the fight.
What to do when you don’t have the evidence
If you reach a case and the game says you don’t feel you have enough evidence, the Justice ACT won’t run yet. Use Kris’ ACT on Blue and choose Evidence instead. It costs around 20% TP, and Blue hands over the missing item so you can continue. For most players, this hits right after the first two cases, which is why Case 3 often needs an Evidence pull before you can accuse Aqua.
Surviving the attacks between trials
This battle leans on the trials far more than on dodging, so taking a few hits won’t lose the fight. If a party member goes down, use Blue’s Integrity ACT to revive everyone at the cost of TP, and use Ralsei’s heal spell to top off health. Damage only makes the fight longer, not unwinnable.
- A blue-dotted line forms into a flower and fires bullet petals; weave between them as several flowers stack in the box.
- Flowers appear before firing, turning their petals into moving obstacles — the same dodging approach as the first attack.
- Music notes scroll across while petals rain from the top and bottom; slip between the wavy lines and watch the falling petals.
- Tiny ballerinas cross the bottom and jump on an every-other pattern; sit between two and shift your heart over the one about to leap.
How you know the fight is over
Clearing the fourth case is the trigger. Once Blue is named with the BlueString and confesses, Yellow becomes shocked, a cutscene plays, and the battle ends. You’re then free to push deeper into the castle in the back half of the chapter.
If a case doesn’t resolve, it’s almost always one of two reasons. Either you picked the wrong culprit or wrong evidence, which loops the previous turn’s attack, or you didn’t have the right evidence on hand and need to pull it from Blue with the Evidence ACT before Justice will work. Keep the Justice and Evidence ACTs in mind on every turn, build TP when you’re short, and the four answers above carry you through to Yellow’s surrender without a wasted trial.
