Let me tell you, when I logged in back in the day and saw Dr. Ratio sitting there as a free gift, I almost fell out of my chair! I thought, 'Surely, this has to be a trick. A free character? They must be terrible!' But oh, how wrong I was. This isn't just any free unit; this is a single-target annihilation machine, a true Hunt unit that lives to relentlessly pursue and pulverize one enemy at a time. But to unlock that god-like power, you can't just slap any old gear on him. You need to build him right. And in 2026, with all the new knowledge we have, I'm here to give you the definitive, most exaggeratedly powerful guide to building the one and only Dr. Ratio!

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First, Let's Talk RELICS: Dressing for Success (and Destruction)

Choosing relics for Dr. Ratio isn't about fashion; it's about function—the function of making enemies disappear. As an Imaginary damage dealer, he has some stellar options that make him hit like a freight train.

  • The Dream Set: Wastelander of Banditry Desert (4-Piece)

    This set is practically made for him! It gives him a straight-up 10% Imaginary DMG boost. But the real magic happens when the enemy is debuffed—he gets a juicy 10% Crit Rate. And if you're lucky enough to have them Imprisoned? Boom! An extra 20% Crit DMG on top. It's a set with conditions, but when those conditions are met, the numbers go BRRRR.

  • The Safe & Powerful Combo

    Not every enemy has an Imaginary weakness, right? So, playing it safe but still powerful is totally valid. Combine 2-Piece The Ashblazing Grand Duke with 2-Piece Wastelander of Banditry Desert. This gives you a reliable, unconditional 10% Imaginary DMG and a massive 20% boost to his all-important Follow-up Attack DMG. No gimmicks, just pure, unadulterated power.

  • The Niche Nuclear Option: Prisoner in Deep Confinement (4-Piece)

    This one is for the mad scientists among us. If you run Dr. Ratio with a team full of Nihility characters who spam Damage-over-Time (DoT) effects like confetti, this set lets him ignore up to 18% of the enemy's DEF. That's like their armor is made of paper! It's situational, but in the right team, it's absolutely busted.

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Planar Ornaments: The Icing on the Annihilation Cake

Now for the cherry on top—the Planar Ornaments. These are non-negotiable for maximizing his potential.

  1. 🏆 Inert Salsotto (2-Piece): THE BEST. Hands down. No debate. It boosts his Crit Rate, and more importantly, it buffs the damage of his Ultimate AND his Follow-up Attacks. Since his entire damage profile revolves around these two things, this set is a perfect match. It's like they designed it with him in mind!

  2. 💥 Space Sealing Station (2-Piece): The Classic. Can't go wrong with a big, fat ATK% increase. It's straightforward, reliable, and makes all his numbers bigger. A solid choice if your Salsotto pieces have terrible substats.

  3. ⚡ Firmament Frontline: Glamoth (2-Piece): The Speed Demon's Choice. Planning to build a Dr. Ratio that outspeeds everyone? This set rewards high Speed with increased DMG. It's a bit more advanced, but if you can hit the speed thresholds, the payoff is sweet.

Light Cones: Choosing His Weapon of Mass Deduction

His weapon is his paintbrush, and the battlefield is his canvas... of destruction. Here are the masterpieces you can equip.

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Light Cone Why It's Absolutely Insane
Baptism of Pure Thought This is his SIGNATURE weapon. It came with his banner, and it's tailor-made for him. The stats and effects synergize with his kit so perfectly it should be illegal. If you have it, use it. Period.
Worrisome, Blissful Topaz's signature cone is a BEAST on Dr. Ratio. It buffs Crit Rate, massively boosts Follow-up Attack DMG, AND debuffs the enemy. It feeds him everything he craves on a silver platter. A top-tier alternative.
Swordplay (Superimposition 5) Don't underestimate this 4-star option! He attacks the same target so many times in one rotation that he can max out its stacks almost instantly, granting a huge, consistent DMG% buff. It's shockingly good.
Sleep Like the Dead It's simple: huge 5-star base stats and a passive that gives a chunk of Crit DMG. Sometimes, you just need to hit harder, and this cone ensures he does.
In the Night While it doesn't buff his Follow-ups directly, the massive 18% Crit Rate it provides is nothing to sneeze at. It also boosts his Skill and Ultimate damage, which is always welcome. A great stat stick.

Trace Priority: Where to Invest Your Precious Resources

You can't level everything at once! You need a plan. Here’s the order that will get him dealing insane damage the fastest:

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  1. Talent (Priority #1) 🚀 - This is the CORE of his kit. His Follow-up Attacks are triggered by his Talent. Leveling this directly increases the damage of his most frequent and powerful attacks. MAX THIS FIRST!

  2. Ultimate (Priority #2) 💢 - His Ultimate not only deals big damage but also applies a crucial debuff that enables his own Follow-up Attacks. It's a key part of his rotation and damage engine.

  3. Skill (Priority #3) ⚔️ - His main spammable attack. It deals good damage and helps trigger his Talent. Important, but comes after the two bigger damage sources.

  4. Basic ATK (Priority: Basically Never) 🥱 - You can leave this at level 1 forever. You'll almost never use it if you're playing him correctly. Save your resources!

So there you have it! Building Dr. Ratio isn't just about putting on gear; it's about crafting a masterpiece of logical destruction. This guide is your blueprint. Now go out there, debuff your enemies, and watch as the good Doctor deduces their complete and utter defeat! Remember, he was free, but his power is absolutely priceless. 💥