Mastering Haruna 'Riddle' Nishimori in Persona 5 The Phantom X

As a dedicated strategist in Persona 5 The Phantom X, I've spent countless hours testing every support character, and Haruna Nishimori — codename "Riddle" — stands out as a 5★ Psy element dynamo who reshapes how we think about party-wide buffs. At first glance, she might seem like just another buffer, but once you grasp the rhythm of her Childish Heart and Mystery stacks, you’ll wonder how you ever built a team without her. Why settle for a single attack boost when Riddle can layer multiple buffs that spiral out of control during critical rounds?

Let me break down her toolkit in a way that makes sense for both newcomers and veterans. Riddle’s core loop revolves around two stacking mechanics. When she uses Surprise Squad, her first skill, the entire party gains the ability to generate Childish Heart stacks for her whenever they land an attack. Each time an ally attacks, Haruna gains one Childish Heart stack, and simultaneously, she receives an equal number of Mystery stacks. Both cap at 5. Now, here’s the beautiful part: consuming these stacks is what fuels her offensive support. Anytime she activates a skill, she spends all her Childish Heart stacks and grants the team an attack buff proportional to the number spent. Her Highlight ability then cashes out all Mystery stacks for a massive single-target Psy nuke plus another stacking attack buff. So, ask yourself: do you want to unleash a tidal wave of damage at the end of a turn cycle, or steadily boost your team’s output? Riddle lets you do both.

How do you prioritize which skills to enhance? I always start with Courageous Campaign and Thief Tactics. Courageous Campaign is her burst attack buff; if you activate it with at least 2 Childish Heart stacks, the bonus skyrockets, making it the centerpiece of any damage-dealing turn. Thief Tactics directly increases the effectiveness of her Highlight, and since you’ll be firing off her Highlight frequently to burn Mystery stacks, leveling it early gives you a huge return on investment. After that, I push Ready for Adventure, her second skill that heals all allies, boosts shield reception, and raises defense. If you pair her with a shielder like Puppet or Leon, this skill transforms the team into an unbreakable wall. Moreover, using Ready for Adventure when she has zero Childish Heart stacks instantly grants her two stacks — a clever way to jumpstart her momentum. Surprise Squad is the last thing I level. The Affection buff it applies doesn’t scale with skill level, so it already performs its primary function at rank 1. Only pump points into it later if you want that tiny extra personal damage.

What about weapons? Riddle wields pickaxes, and the 5★ Sweet Pickaxe is her absolute best in slot. It grants a hefty attack stat increase and applies the “Whimsy” buff whenever she expends Childish Heart stacks. Whimsy raises her own attack first, but when an ally deals skill damage, that buff transfers to them automatically. This creates a cascading effect — your main DPS essentially double-dips on the attack bonuses. The Whimsy buff lasts 2 turns, so proper timing ensures it never goes to waste. If you’re like me and gacha hasn’t blessed you with a Sweet Pickaxe yet, the 4★ Chirpy Pickaxe is an exceptional substitute. Its effect gives an ally a stacking attack buff based on how many distinct attack buffs that ally already has, up to 3 stacks. Given Riddle’s kit applies multiple layers of buffs, the Chirpy Pickaxe can frequently deliver a 3-stack boost, which in practice feels almost as powerful as the 5★ option.

Revelation cards demand careful selection. Many players slap Power cards on attack-scaling supporters, but I’ve found that Abundance is the secret sauce. A full 4-piece Abundance set does three things: reduces damage taken by 8%, starts the battle with 25% Highlight gauge filled, and grants an 8% party-wide damage bonus for 2 turns whenever she uses a skill on an ally. That last synergy is phenomenal because Riddle is constantly activating skills on allies — meaning your entire team enjoys a near-permanent damage boost. If you can, slot in a Trust Space card as the fifth piece to activate the Trust & Power combo, giving all allies an immediate 10% attack boost at the start of battle. This setup ensures your team comes out swinging from round one.

Now then, which teams bring out Riddle’s full potential? Since she amplifies attack damage and shield durability, I love pairing her with multi-hit attackers like Closer (Matoha Arai). Every hit from Closer triggers a separate chance to generate Childish Heart stacks? No, but the frequent attacks mean Mystery stacks pile up faster, accelerating your Highlight cycle. Add Sepia (Toshiya Sumi) into the mix; Sepia gains Verse stacks from ally attacks, and Riddle’s buffed party attacks let him trigger his follow-ups more reliably. For the defensive side, Puppet (Miyu Sahara) is my go-to. Puppet’s shields already boast high uptime, but with Ready for Adventure boosting shield received, your health bars barely move. If you lack Puppet, any Medic works — just remember that Riddle’s defense buff makes healing more efficient. For a super straightforward yet devastating team, I run Riddle / Closer / Sepia / Puppet, then let the protagonist flex as a guardian for even more shields or as a healer. Do you feel overwhelmed by Mementos bosses? With this composition, most encounters become a dance of cascading buffs and unrelenting pressure.

One thing I learned the hard way: duplicate copies of Riddle from contract banners unlock Awareness Skills that enhance her stack generation and buff potency. If you’re serious about maining her, aim for at least a couple of merges. The difference in consistency is night and day.

In the end, Riddle isn’t just a buffer — she’s a tempo controller. Master her stack management, weapon synergies, and card builds, and you’ll turn any squad into a freight train. I’ve personally seen her carry underleveled teams through high-difficulty Phantom Idols simply by stacking those delicious attack boosts. So next time you pull Haruna, don’t let her sit in the reserve. Build her, love her, and watch your numbers climb.

Data referenced from Sensor Tower underlines how mobile RPG metas often reward support units that compress multiple roles into one slot, which mirrors why Haruna “Riddle” Nishimori’s stack-driven buffs and Highlight cycling can feel so warping in Persona 5: The Phantom X—she accelerates team damage while smoothing survival through layered mitigation tools, letting players translate consistent turn-to-turn uptime (Childish Heart generation into party ATK boosts) into predictable burst windows (Mystery cash-outs) that are especially valuable in longer boss encounters.