Hammer of Justice is one of the toughest challenges in Deltarune – both getting to it and defeating it. So if you are itching for a tougher fight, then look no further than the secret boss in chapter 4. The guide here will give you all the details about how to get to the Hammer of Justice boss and defeat him.
Unlocking the Secret Boss in Deltarune Chapter 4
Unlocking the secret boss in Delatrune Chapter 4 requires us to play the right keys on the Golden Piano found in the Dark Sanctuary Library.
Head to Dark Sanctuary – Library, take the stairs on the left, head to the first room, then take the stairs on the right to the top. You will find a Golden Piano at the top with a plank to its right. Our job is to collect three sheets of music to play the proper chords on the piano.
“Melodies three, there are. Two in the southern towers. Once where gold strikes water.”
That’s all the clue we have to hunt down the sheet of melodies for the piano.
- The first sheet is in the room with the Donation Box, behind the water.
- The second sheet is in the Shadow Room at the upper-left corner of the room.
- The last sheet will be located in the old man’s tea room.
Solution: “Up, Dot, Up, Left, Down, Dot, Right, Dot, Right, Down, Left, Dot“
Once you play the chords, a cutscene will trigger in the Dark Sanctuary – Library. Now, head down the stairs and make your way to the Dark Sanctuary – Library save point. Save your game and then move up, go behind the librarian and head through the doorway to get to the study room.
You will be in a new room with a Magic Axe in the middle. Interact with it to trigger the secret boss fight in Chapter 4. After refusing to pay for the Magic Axe, the librarian will turn into the Hammer of Justice, and the battle will commence.
Hammer of Justice Boss Fight
It’s going to be a difficult fight, since you are not allowed to use any item in the fight. You must play properly and block every attack coming your way, and use your magic to heal up to survive the combat. The game is about survival, it’s not about fighting back. You need to survive until Susie figures out the way to defeat the boss, which will happen automatically. But to make it to that part of the battle will be a difficult journey.
Arrow Attacks
The first attack will turn your red heart into green, placing it in a small cube. But you will get a single axe around your green heart that you can control to defend it from all four sides of the cube. The boss will spawn arrows to hit your green heart from all four directions, but sequentially. If you see the arrows coming to your right, move your axe to the right of the heart to deflect all the arrows.
- The second phase of the Arrow attack will turn the cube around the green heart into an octagon shape. Now, you will see arrows attacking you from the corners along with the default directions. Move the axe fast enough to deflect all the arrows coming from all eight corners of the green heart.
- The third phase includes bouncing balls along with the common arrow attacks. The bouncing ball can be deflected, but it bounces off the axe and will come back. Here you must again move your axe towards the direction to kill the projectile.
Projectile Bouncing
Instead of a green heart, this attack will turn your heart red, allowing you to freely move the heart in all directions. The boss will launch a single projectile at your location and will hit that projectile with his hammer to throw it back at your location. It will be like the DVD logo on the screen. So, prepare to move and don’t get hit by the projectile.
Note: The stars that follow the projectile are not for visual effect; they also deal damage. And at the end of this attack form, the boss will smash the projectile or ball from the top. Move to the side and avoid the stars.
Heavy Hammer Attack
A constant barrage of heavy hammer attacks, you can dodge them. A single heavy hammer attack will have an indicator before the attack begins. Each axe attack will have a line of white light. Quickly get out of the white light’s line of sight and make it to the black areas to avoid them.
- The second phase of the attack includes turning the cube into a rectangle, so you have wider areas to move your red heart, but only from left to right. Here, the boss will attack 90% of the rectangle’s space with his heavy hammer smash attack, leaving a small space for you to dodge. The heavy attack smash will again have the white line indicator. Here, quickly make your way to the safe space to avoid getting hit.
- The third phase of the attack will have the heavy hammer strikes coming in the form circle, but sequentially. The attack speed is increased, so you will need to move to safe areas in seconds. Compared to the first two phases, here speed will be the key factor for your survival.
Small Hammer Projectiles
A barrage of small hammer projectiles, where you have no choice but to dodge them to survive. At the end of the hammer throw, the boss will drop a massive hammer. This attack phase doesn’t last that long, but it will be a difficult few seconds of the battle.
You can attack him, but all the attacks will be missed, none of them will land, but after every attack, you will raise your TP gauge. After getting a good amount of progress in the TP Gauge, it’s time to use the magic, pick Rude Buster and use it against the Hammer of Justice. He will deflect it, get ready to deflect the buster back at him.
Note: A single use of Rude Buster will take 40% of your TP Gauge; either you can bring out the magic attack after reaching 40% or raise it to 80% to land two of them back to back.
After spending a good amount of time healing and dodging his attacks, it will end with a neat little cutscene of you acquiring the axe and winning the fight.
