Dr. Ratio is one of the most powerful single-target characters in Honkai: Star Rail. He’s a debuff-based DPS whose damage scales with the number of debuffs applied on an enemy. Because of this, he’s a great main in debuff-heavy lineups. His Technique follow-up attack is also very effective in a Tech-heavy lineup. For those of you who’ve already unlocked him, here’s a full guide to Dr. Ratio’s kit, Eidolons, relics, lightcones, and main and sub relic stats.
Dr. Ratio’s Kit and Eidolons
Dr. Ratio is an Imaginary-type character who follows the Path of the Hunt. He’s one of the best characters in Honkai for dealing single-target damage. His kit centers around using debuffs to boost his damage. This makes him super-effective against bosses and elite-level enemies.
Dr. Ratio’s Moveset
| Attack Type | Name | Description |
|---|---|---|
| Basic ATK | Mind is Might | Deals Imaginary DMG equal to 100% of ATK (single target) |
| Skill | Intellectual Midwifery | Deals Imaginary DMG equal to 150% of ATK (single target) |
| Ultimate | Syllogistic Paradox | Deals Imaginary DMG equal to 240% of ATK (single target) |
| Talent | Cognito, Ergo Sum | Skill has a 40% chance of follow-up attack, which deals Imaginary DMG equal to 270% of ATK (single target) |
| Technique | Mold of Idolatry | Creates a Special Dimension that Taunts enemies (10s). 100% to reduce SPD by 15% for 2 turns to enemies inside the dimension. |
Dr. Ratio’s Ascensions
| Ascension Level | Effect Name | Effect Description |
|---|---|---|
| A2 | Summation | Skill increases CRIT Rate by 2.5% and CRIT DMG by 5% for every debuff on target. Up to 6 stacks. |
| A4 | Inference | Skill has a 100% chance to reduce Effect RES by 10% for 2 turns. |
| A6 | Deduction | Deals 10% bonus DMG for every debuff on targets with 3 or more debuffs. Maximum 50% bonus DMG. |
Dr. Ratio’s Eidolons
| Eidolon Level | Eidolon Name | Description |
|---|---|---|
| E1 | Pride Comes Before a Fall | Increases max Summation (A2) stacks by 4. Starts battles with 4 Summation. |
| E2 | The Divine Is In theDteails | Follow-up attack deals Imaginary DMG equal to 20% of ATK for every debuff on the target. Can be triggered up to 4 times per follow-up attack. |
| E3 | Know Thyself | Increases Ultimate Lv. by 2 (up to Lv. 15) and Basic ATK Lv. by 1 (up to Lv. 10) |
| E4 | Ignorance is Blight | Regenerates 15 Energy each time follow-up attack is triggered. |
| E5 | Sic Itur Ad Astra | Incresaes Skill Lv. by 2 (up to Lv. 15) and Talent Lv. by 2 (up to Lv. 15) |
| E6 | Vincit Omnia Veritas | Adds 1 triggerable count for Wiseman’s Folly. Increases DMG of Talent follow-up attack by 50%. |
Best Lightcones for Dr. Ratio
Dr. Ratio’s follow-up attack allows him to attack outside of his own turn. To maximize his damage potential, you’ll want to focus on Lightcones that boost his CRIT DMG and CRIT Rate.
BEST – Baptism of Pure Thought
Dr. Ratio craves CRIT boosts, so his own Signature Lightcone is the best pick, by far. This Lightcone boosts his CRIT DMG by 20%, with an extra 8% for every debuff on the target (up to 3 times). With all three stacks applied, Dr. Ratio gets a massive 44% CRIT DMG buff.
With this Lightcone equipped, Dr. Ratio gets a Disputation buff whenever he casts his Ultimate. This effect increases DMG by 36% and allows his follow-up attacks to ignore 24% target DEF.
Worrisome, Blissful
While not as good as Baptism Pure Thought, this Lightcone does offer similar boosts to the stats Dr. Ratio needs. Worrisome, Blessful grants a 18% CRIT Rate bonus and 30% DMG bonus to Dr. Ratio’s follow-up attacks.
Anything that Boosts CRIT Rate or CRIT DMG
For Dr. Ratio, no other Lightcones come close to the two mentioned above. If you don’t have either, pick any Lightcone that boosts CRIT Rate, CRIT DMG.
Best Relics for Dr. Ratio
BEST – Pioneer Diver of Dead Waters
You won’t find a more perfect set for Dr. Ratio. This Relic set boosts DMG, CRIT Rate, and CRIT DMG against enemies with lots of debuffs. You’ll want at least 2 pieces to get the 12% DMG boost against enemies with debuffs. You’ll always want to be working toward the full set, though. That extra CRIT Rate and CRIT DMG is just too much to pass up.
Main/Substats
- Feet – Speed: Dr. Ratio has a breakpoint of 134 SPD. That means at that speed and higher, he can act twice before the enemy’s turn comes around. As a debuff-based DPS, this means he can do twice as many moves before enemy debuffs time out.
- Body – CRIT Rate/CRIT Dmg: A rule of thumb in Honkai is you want a CRIT Rate/CRIT DMG ratio of about 1:2.
- Orb – Imaginary DMG or ATK %: Either is good. Choose this slot based on whatever has the best substats for your build.
- Link Rope – ATK %: To increase DMG output.
How to Play Dr. Ratio
Dr. Ratio’s playstyle revolves around the massive CRIT boosts he gets from debuffs applied to targets. For example, at A2, he gets boosts to CRIT Rate and CRIT DMG for every debuff on his attack target. At A6, he gets a massive DMG bonus on top of that.
This means you want to maximize Dr. Ratio’s passives by pairing him with characters who can apply multiple debuffs. Characters like Silver Wolf, Pela, and Welt are all great team options for Dr. Ratio.
Also, so much of Dr. Ratio’s effectiveness depends on maximizing his Talent’s follow-up attack. Ideally, you want to trigger his follow-up attack as often as possible. Building for CRIT Rate and CRIT DMG is the most efficient way to optimize his DMG output.
A typical loop when using Dr. Ratio as a main would look like this:
- Launch his Skill to reduce Effect RES (A4).
- Apply as many debuffs as you can with your other characters.
- Use Dr. Ratio’s Ultimate to deal massive DMG.
- Deal DMG on the enemy with Wiseman’s Folly to trigger Dr. Ratio’s Talent follow-up attacks.
