Spoilers: This guide reveals the optional Chapter 4 boss, its route, the golden piano code, and its rewards. The boss is the Hammer of Justice, Gerson’s alternate form. Unlock the encounter before progressing up the tower near the start of the Dark Sanctuary; after that story point, it becomes unavailable.
How to unlock the Chapter 4 secret boss
- Defeat Jackenstein in the Dark Sanctuary. You’ll receive climbing gear, which opens routes in the Study.
- Backtrack through the Study and collect the three music pieces. Explore the newly accessible climbing routes. The pieces are found in a climbing challenge that ends in a miniboss, a dark room with statues, and along the route behind a fountain. The golden piano records each piece as you find it, so you do not need to memorize them. Finding the pieces is optional if you already know the piano sequence.
- Reach the golden piano. Go through the upper Study door and climb the books near the save point.
- Enter this sequence: Up, dot, up, left, down, dot, right, dot, right, down, left, dot.
- Go to the fireplace in the Study. The solved piano opens a hidden passage there. Follow it and interact with the JusticeAxe to start Gerson’s challenge.
The plaque’s clue reads: “Melodies three, there be. / Two in the southern towers / One where gold strikes water”.
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How to beat the Hammer of Justice
Susie fights alone. Gerson dodges attacks, so this is not a conventional boss fight won by reducing his health to zero. Your goal is to survive his attack patterns and impress him through Susie’s actions until the final attack sequence begins.
Block and dodge the attack patterns
Use the green-SOUL axe blocking to meet incoming projectiles, and switch to red-SOUL movement to dodge. The blocking patterns progress from four directions to diagonals. Watch for arrows, shells that can take multiple blocks, hammers, and direct attacks; choose your response based on the incoming pattern rather than relying on one defense throughout.
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Build progress while staying alive
Healing with OKHeal adds impression progress, and a successful counter-deflection of Rude Buster contributes substantially. Ordinary attacks can also help impress Gerson, but they do not defeat him by dealing damage. Use them as an optional way to progress, not as a strategy for draining a health bar.
Prioritize avoiding hits and healing when Susie needs it. Defend when a dangerous attack is coming; on safer turns, consider actions that build TP or advance the encounter. Some walkthroughs advise avoiding attacks, while others suggest attacking between heals. The useful distinction is that attacks do not work as a damage route, though actions that impress Gerson can help move the fight forward.
Rank #2
- Populate your island with Mii characters and watch them come to life
- Base your Mii characters on family and friends, or whatever you want—and customizer, including some face customization options you haven’t seen before
- Pick your Mii characters up and place them near each other to chat and hang out
- Help your Mii characters explore likes and dislikes, find relationships, and get up to all sorts of fun
- Give Mii characters clothes, food, items, and life advice as they deal with all kinds of situations
If you lose
A loss does not permanently lock you out of the encounter; you can try again. Gerson may offer the rewards after a loss, but Susie can refuse them until she wins.
Quick Recap
Best Value
- Live the life of a Pokémon Trainer in the streets of Lumiose City!
- For the first time in the Pokémon RPG series, command your Pokémon in real-time battles
- Use the power of Mega Evolution in battle and take on rampaging Rogue Mega-Evolved Pokémon
- Compete in the Z-A Royale each night to test your skills and try to become the strongest Pokémon Trainer
- Visit shops, restaurants, and places called wild zones—where Pokémon roam free—all centered around Prism Tower
Rank #3
- New stages and fighters are joined by the combined rosters of every past Super Smash Bros. Game
- Challenge others anytime, anywhere, whether you're on the couch or on the go
- Play any way you want—locally, online, in TV mode, Tabletop mode, Handheld mode, or even with GameCube Controllers
- Fight faster and smarter with new and returning techniques, like the perfect shield and directional air dodge
- Face off in 2-4 player battles, or play against the computer
What you get for winning
- The JusticeAxe
- A Shadow Crystal
- A permanent +4 to Susie’s Magic stat
- An upgrade to Susie’s OKHeal spell: BetterHeal
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