Dr. Ratio Build Guide, Abilities, and Best Teams - Honkai: Star Rail Guide - IGN (2024)

Honkai: Star Rail's Dr. Ratio wants to educate the whole universe in his battle against ignorance. That's quite the undertaking, but luckily for us, Dr. Ratio has plenty of time to join us in battle and obliterate the enemy with his devastating follow-up attacks.

From the best Light Cones and Relics to the best teams, these are our recommendations for the best Dr. Ratio build, plus everything else you might want to know about Honkai: Star Rail character Dr. Ratio.

How to Get Dr. Ratio

Dr. Ratio joined the roster of playable Honkai: Star Rail characters on January 17, at the start of phase 2, version 1.6. Dr. Ratio is an Imaginary character who follows the path of The Hunt. Unlike most of his 5-star peers, Dr. Ratio is available as a free character - just log in to Honkai: Star Rail between his release date and the start of version 2.2 to claim him as a reward. Beware that you need to have completed the Trailblaze Mission called ‘A Moment of Peace’, which is one of the first main missions in the game (part of the Today Is Yesterday's Tomorrow quest series.

Dr. Ratio will also be featured on a Character Event Warp banner. You can exchange one special star rail pass to get one “warp”; one chance to obtain an additional Dr. Ratio. If you’ve unfortunately missed this free 5-star character, you’ll have to wait for a rerun banner.

Dr. Ratio Stats

Dr. Ratio Abilities

• Basic Attack: Deals Imaginary DMG equal to 50% of Dr. Ratio's ATK to a single target enemy.
• Skill: Deals Imaginary DMG equal to 75% of Dr. Ratio's ATK to a single target enemy.
• Ultimate: Deals Imaginary DMG equal to 144% of Dr. Ratio's ATK to a single target enemy and applies Wiseman's Folly. When Dr. Ratio's allies attack a target afflicted with Wiseman's Folly, Dr. Ratio launches his Talent's follow-up attack for 1 time against this target. Wiseman's Folly may be triggered up to 2 times and only affects the most recent target of Dr. Ratio's Ultimate. This trigger count resets after Dr. Ratio's Ultimate is used.
• Talent: When using his Skill, Dr. Ratio has a 40% fixed chance of launching a follow-up attack against his target for 1 time, dealing Imaginary DMG equal to 135% of Dr. Ratio's ATK. For each debuff the target enemy has, the fixed chance of launching a follow-up attack increases by 20%. If the target enemy is defeated before the follow-up attack triggers, the follow-up attack will be directed at a single random enemy instead.
• Technique: Creates a special dimension that Taunts nearby enemies, lasting for 10 seconds. After entering battle with enemies in this special dimension, there is a 100% base chance to reduce each single enemy target's SPD by 15% for 2 turns. Only 1 dimension created by allies can exist at the same time.

Dr. Ratio is a DPS whose damage stems from his direct- and follow-up attacks. His Skill may seem mediocre at first, as it’s basically a slightly better version of his Basic Attack, but using the Skill will trigger the Talent’s follow-up attack, thus greatly improving the total damage. Beware of the 40% fixed chance for the follow-up attack to trigger - if you want a 100% fixed chance, the enemy target needs to suffer from at least three debuffs.

Beware that Dr. Ratio’s Ultimate ability, which applies the Wiseman’s Folly status effect, does not count as a debuff. Luckily, it still triggers a maximum of two additional follow-up attacks whenever an ally hits the target enemy, which translates to a ton of extra attack damage.

Unlike the Talent’s follow-up attack, beware that Dr. Ratio’s Technique has a "base chance" of reducing an enemy’s Speed (instead of a fixed chance), which means that the 100% chance will be diminished by the enemy’s Effect Resistance stat. Although the base chance could be improved with the Effect Hit Rate stat, it’s best not to prioritize this in your Dr. Ratio build as the Technique isn’t one of his most important abilities. As long as you target normal opponents (no bosses), their 0-20% Effect Resistance still gives you a pretty good hit chance.

Dr. Ratio Traces

• Summation (bonus ability Ascension 2): For every debuff that’s on the target when Dr. Ratio uses his Skill, his Critical Rate increases by 2.5% and his CRIT DMG by 5%. This effect can stack up to 6 times.
• Inference (bonus ability Ascension 4): When the Skill is used to attack an enemy target, there is a 100% base chance to reduce the attacked target's Effect Resistance by 10% for 2 turns.
• Deduction (bonus ability Ascension 6): When dealing DMG to a target that has 3 or more debuffs, the DMG dealt by Dr. Ratio to this target increases by 10% for each debuff the target has, up to a maximum increase of 50%.

Let’s take a look at Dr. Ratio’s Trace Bonus Abilities first. Summation is great: you’ll get a whopping 15% Critical Rate and 30% Critical Damage increase if you reach the max stack of 6, which makes it much easier to create a proper Dr. Ratio build, especially if you don't have the best Light Cones and Relics yet. The Inference Trace Ability is also a very helpful one to have; it allows Dr. Ratio to lower the enemy’s Effect Resistance, making them more vulnerable to debuffs which, in turn, helps Dr. Ratio deal more damage. Also, the effect itself counts as a debuff. The Deduction Trace Ability simply improves damage for each target debuff, up to 50% extra damage (5 debuffs).

To get the best Dr. Ratio build, make sure you upgrade his minor Trace Bonuses too: Critical Rate and Attack. The Defense boost isn’t important.

As for the active abilities, try to upgrade Dr. Ratio’s Talent Trace Levels first, but keep in mind that this only upgrades the damage dealt by the follow-up attack; the fixed chance to trigger the attack is still 40% (plus 20% more per debuff). Next, upgrade his Ultimate and Skill - there’s no need to improve his Basic Attacks as you (ideally) won’t be using them.

Dr. Ratio Eidolon Levels

Most of Dr. Ratio’s Eidolon Levels serve the same purpose; to increase his damage and especially that of his follow-up attacks. If you have enough Warps left, Eidolon Level 1 would make a strong improvement as it allows Dr. Ratio to get a total bonus of 25% Critical Rate and 50% Critical Damage.

Eidolon Level 4, on the other hand, greatly improves his Energy Regeneration. If you only use his Skill (without Basic Attacks), have a high Speed, and make sure the follow-up attack always triggers, you’ll get a ton of extra Energy from this Eidolon upgrade.

That said, a Dr. Ratio build without Eidolon Levels can still give you a powerful DPS. If you’re considering getting the first Eidolon Level, remember that Dr. Ratio releases alongside his signature Light Cone, Baptism of Pure Thought, which you might want to get instead.

Best Dr. Ratio Build

Here's an overview of the best Light Cones, Relics, Planar Ornaments, and stats for your Honkai: Star Rail Dr. Ratio build.

Best Dr. Ratio Light Cones

The best Light Cone for your Dr. Ratio build is the 5-star Baptism of Pure Thought. This probably doesn’t require much explaining; it’s the only Light Cone to perfectly complement his debuff-related follow-up attacks, complete with a massive Critical Damage bonus and a temporary Defense-lowering effect.

Don’t worry if you don’t have the signature weapon though; most Light Cones from The Hunt path offer follow-up attack bonuses, Critical Rate boosts, or Critical Damage boosts, which makes most of them suitable for your Dr. Ratio build. Another 5-star option that stands out is the Worrisome, Blissful Light Cone, as it increases both Critical Rate and follow-up damage. On top of that, it applies an extra debuff to the enemy target.

The best 4-star Light Cone for Dr. Ratio is Swordplay, as it outperforms all other 4-stars (and some 5-stars) under the right circ*mstances. If your allies keep hitting a boss enemy while Dr. Ratio's Ultimate is active, and he himself targets the boss with his Skill, you should be able to reach the maximum bonus - resulting in an impressive damage increase for your Dr. Ratio build.

Best Dr. Ratio Relics

It’s surprisingly easy to find suitable Relics for your Dr. Ratio build. Although it’s best to use sets that improve Imaginary damage, damage against debuffed enemies, and follow-up attack damage, sets with attack and speed bonuses work fine for early-game Dr. Ratio builds (such as the 2-piece Musketeer and Messenger sets).

The best Relic set for your Dr. Ratio build, however, is the 4-piece Wastelander of Banditry Desert set, as it grants him an Imaginary damage boost (improves all of his attacks rather than just the follow-ups) plus extra Critical Rate and Critical Damage. Dr. Ratio needs to attack debuffed enemies anyway, so you’ll have no trouble keeping the 10% Critical Rate bonus active at all times. Just beware that the Critical Damage boost only works against Imprisoned enemies; enemies who suffer the Weakness Break Effect from Imaginary damage.

If your Dr. Ratio build doesn’t require additional Critical Rate, you can also combine the Wastelander set with the 2-piece Ashblazing Grand Duke Relic set. It’s best not to use the full 4-piece Ashblazing set, however, as it requires a ton of stacks which will be reset upon triggering another follow-up attack.

The best Planar Ornament set for your Dr. Ratio build is the Inert Salsotto set - with its Critical Rate and follow-up attack bonuses, it's simply perfect for his kit. Keep in mind that those bonuses require a Critical Rate stat of at least 50%.

Best Stats

• Body: Critical Damage, Critical Rate
• Feet: Speed, ATK%
• Planar Sphere: Imaginary Damage Boost
• Link Rope: ATK%, Energy Regeneration Rate
• Sub stats: Critical Rate, Critical Damage, Effect Hit Rate, Speed, ATK%

The most important stats for your Dr. Ratio build are Imaginary Damage Boost, Critical Damage, and Critical Rate. Ideally, you should go for Critical Damage on the Body slot and get your Critical Rate from other sources. Considering that Dr. Ratio receives a 12% Critical Rate increase from his minor Trace stats and 2.5% Critical Rate per buff from his Summation Trace, he’ll typically have a 27-32% Critical Rate (with four to six active buffs) even without the rest of his build. If you’re using the Inert Salsotto Planar Ornament set and manage to get some Critical Rate substats on your Dr. Ratio Relics, you’ll most likely be able to add at least another 20% Critical Rate, which would be enough to activate Inert Salsotto’s full set effect.

The Link Rope presents us with another difficult choice to make: Energy Regeneration, or more Attack Power? Since Dr. Ratio is a DPS whose damage largely stems from his follow-ups and Skill, it seems a bit wasteful to dedicate an entire Relic stat to Energy Regeneration, even if it helps him land more follow-ups. It’s therefore better to get the Energy boost from an ally (looking at you, Tingyun).

The most important subsidiary stats are either Critical Rate or Critical Damage, depending on the rest of your Dr. Ratio build: if you’ve chosen Critical Damage as a main Relic stat, it’s probably best to focus on Critical Rate as a subsidiary stat and vice versa. Extra Speed and Attack is always welcome, while having some extra Effect Hit Rate would improve the Technique’s hit chances.

Best Teams for Dr. Ratio

Finding the best team composition for Dr. Ratio is very important; to trigger his follow-up attacks, he needs his allies to implant debuffs on his opponents. Remember: the opponent needs to suffer from three debuffs to give the follow-up attacks a 100% fixed chance, but they’ll need to suffer from at least five debuffs to trigger the full bonus from the Deduction Trace Ability. One debuff support may not even be enough for your Dr. Ratio team!

Another thing to keep in mind is the Ultimate's uptime; the sooner Dr. Ratio can cast it, the better, so consider teaming him up with Energy-boosting supports. Since Dr. Ratio himself is a Skill Point negative character (he should never use his Basic Attack), it's best if the support is able to generate a lot of Skill Points for him. Finally, any support who can improve follow-up attack damage or weaken the enemies' resistance to follow-up attacks would make a great addition to a Dr. Ratio team.

Here are two of the best Dr. Ratio teams you can get:

Dr. Ratio & Topaz Team

With Topaz and Numby on board as a sub-DPS and support hybrid, this is the Dr. Ratio team of a billion follow-up attacks. As Topaz and Numby's Skill makes enemies weaker to follow-up attacks (without needing many Skill Points), they make a great DPS duo (or should we say trio?) with Dr. Ratio.

Since this Dr. Ratio team only offers room for a single specialized debuffer, it needs to be a great one; Silver Wolf. She and Dr. Ratio are a match made in heaven as all of Silver Wolf’s attacks have a chance of placing a debuff on the opponent. Debuffs affecting the opponents’ Attack, Speed, and Defense will quickly stack up, allowing Dr. Ratio to deal his maximum amount of damage. If you don’t have Silver Wolf, a character like Pela would make a great 4-star alternative; she doesn’t inflict as many debuffs, but she comes with a handy Effect Hit Rate boost for her teammates.

And finally, since there’s no place left for a specialized support like Tingyun or Bronya, we’ll make do with Huohuo instead; not only does she keep everyone alive, but she also applies an attack buff and improves the team’s Energy Regeneration.

Dr. Ratio Speedy Ultimate Team

This Energy-focused Dr. Ratio team uses Silver Wolf as a debuffer again (replace with another debuffer if you don’t have her) and tasks Tingyun with the role of Dr. Ratio’s personal buff support. Both Tingyun and Silver Wolf have plenty of opportunities to use Basic Attacks, so they won’t hinder Dr. Ratio’s rotation.

Of course, most Harmony characters work well with Dr. Ratio, but Tingyun is especially amazing as she can grant him a ton of extra Energy on top of her attack boosts. Although Bronya would still be a good option thanks to her massive Critical Damage bonus, she lacks the Energy support skills.

As Tingyun already buffs Dr. Ratio’s damage and Energy, you can use Luocha as your healer instead of Huohuo. His ability to heal without consuming Skill Points and remove buffs from the opponent will come in handy. Furthermore, he has the same Elemental type as Dr. Ratio (Imaginary), which makes it easier for Silver Wolf to implant the correct Weakness Type on her opponents (you’ll have three different Elements on the team instead of four).

Need more characters to build the best Dr. Ratio teams? Take a look at our Honkai: Star Rail Warp guide for more info on the Warp system and the current character banners.