Honkai Star Rail’s Dr. Ratio – yes, that’s really his name – is now a member of the playable roster – for free! Upon release, every player got a free copy of him in their mailbox. He’s a follower of the Hunt path and is an Imaginary-using five-star unit. I’m too old to make a ratio-based joke here, but I feel like his hand making an L-shape in his splash art is on purpose.
If you want to stock up on stellar jades, grab all the latest Honkai Star Rail codes right here, and check out our Honkai Star Rail tier list to see who we think are the best characters in the game.
Here is everything you need to know to get a great Honkai Star Rail Dr. Ratio build.
What is the best Honkai Star Rail Dr. Ratio build?
| Best light cone | Baptism of Pure Thought |
| Light cone substitute | Worrisome, Blissful, Swordplay |
| Best relic set | Wastelander of Banditry |
| Planar ornaments | Inert Salsotto |
| Main stats | -Body: crit rate/crit damage -Feet: attack -Planar sphere: imaginary damage boost -Link rope: attack |
| Sub-stats | Crit damage, crit rate, attack, speed |
Would you look at that – Dr. Ratio is yet another tall, male, Imaginary, five-star character. We can now have a full team of them! Anyway, Dr. Ratio follows the path of the Hunt, which means he deals in single target damage akin to Honkai Star Rail’s Yanqing and Honkai Star Rail’s Dan Heng.
His best light cone is his signature, Baptism of Pure Thought, and he works best with a full set of Wastelander of Banditry relics, with attack and crit stats.
How do I use Dr. Ratio?
The key to using Dr. Ratio is to apply debuffs with characters like Honkai Star Rail’s Silver Wolf, Honkai Star Rail’s Welt, or Honkai Star Rail’s Pela – especially if you have her E4 unlocked. This is because his damage increases a lot when he attacks debuffed enemies.
Other than that, attacking the same target until it’s gone will make use of extra damage when enemies have Wiseman’s Folly applied to them.
What are the best light cones for Dr. Ratio?
Dr. Ratio has his own signature five-star light cone, Baptism of Pure Thought, which is tailored to his kit. There are some other great options for him, though, which we’ve listed below. Just make sure to equip him with a cone aligned to the Hunt path.
| Light Cone | Effect | How to obtain |
| Baptism of Pure Thought (five-star) | Increases Dr Ratio’s crit damage by 20%. For every debuff on the enemy target, his crit damage dealt against said target increases by 8%, stacking up to three times. When using his ultimate to attack the enemy target, he receives the Disputation effect, which increases the damage dealt by 36% and enables his follow-up attack to ignore 24% of the target’s defense. This lasts for two turns | Light cone banner alongside Dr. Ratio |
| Worrisome, Blissful (five-star) | This cone increases Dr. Ratio’s crit rate by 18%, and his follow-up damage by 30%. When he uses a follow-up attack, he applies the Tame state to the target, which can stack twice. If allies hit the same target with the Tame state, each stack increases his crit damage by 12% | Light cone banner alongside Topaz |
| Cruising in the Stellar Sea (five-star) | Increases Dr. Ratio’s crit rate by 8%, and increases his crit rate against enemies with HP at 50% or less by an extra 8%. When he defeats an enemy, his attack increases by 20% for two turns | Purchase from Herta’s Store in the Simulated Universe |
| Swordplay (four-star) | Each time Dr. Ratio hits the same target, the damage he deals increases by 8%, stacking up to five times. This effect dispels when he changes targets | All banners |
| Only Silence Remains (four-star) | Increases Dr. Ratio’s attack by 16%. If there are two or fewer enemies on the field, his crit rate increases by 12% | All banners |
What are the best relics for Dr. Ratio?
The best set of relics for Dr. Ratio is the Wastelander of Banditry set, as it not only improves his imaginary damage output but compliments his kit in terms of attacking debuffed enemies.
We all know what farming relics is like, though, so you can mix a two-piece of the Wastelander set with a two-piece of attack- or follow-up damage-boosting pieces, too.
| Relic set | Effect | How to obtain |
| Pioneer Diver of Dead Waters | Two equipped: Increases damage Dr. Ratio deals to debuffed enemies Four equipped: Increases crit rate by 4%. Dr. Ratio deals 8/12% extra crit damage to enemies with two/three debuffs. If Dr. Ratio inflicts a debuff onto an enemy, these effects increase by 100% for one turn |
Cavern of Corrosion: Path of Dreamdive in the Reverie |
| Wastelander of Banditry Desert | Two equipped: Increases imaginary damage Four equipped: When attacking debuffed enemies, Dr. Ratio’s crit rate increases by 10%. If the enemy becomes imprisoned, his crit damage increases by 20% |
Cavern of Corrosion: Path of Conflagration on the Xianzhou Luofu |
| Musketeer of Wild Wheat | Two equipped: Increases attack Four equipped: Dr. Ratio’s speed increases by 6%, and his basic attack damage by 10% |
Cavern of Corrosion: Path of Drifting on Jarilo-VI |
| Ashblazing Grand Duke | Two equipped: Increases follow-up damage Four equipped: When Xueyi uses her follow-up attacks against an enemy, it increases her attack by 5% for every time the follow-up attack deals damage. This can stack up to eight times and lasts three turns. The effect disappears when a follow-up is next used |
Cavern of Corrosion: Path of Darkness on the Xianzhou Luofu |
Planar ornaments
| Relic set | Effect | How to obtain |
| Inert Salsotto | Two equipped: Increases Dr. Ratio’s crit rate by 8%. When his crit rate reaches 50% or above, his ultimate and follow-up attack damage increases by 15% | Immersion Reward devices in World 6 of the Simulated Universe |
| Firmament of Frontline Glamoth | Two equipped: Increases Dr. Ratio’s attack by 12%. When his speed is equal to or higher than 135 or 160, his damage increases by 12% or 18% | Immersion Reward devices in World 8 of the Simulated Universe |
| Space Sealing Station | Two equipped: Increases Dr. Ratio’s attack by 12%. When his speed reaches 120 or higher, his attack increases by 12% | Immersion Reward devices in World 3 of the Simulated Universe |
Relic stat recommendations
In terms of which stats you should aim for when picking out a relic set, here are the ideal results.
Main stats:
- Body – crit rate/damage
- Feet – attack
- Planar sphere – imaginary damage bonus
- Link rope – attack
Sub- stats:
- Crit rate
- Crit damage
- Attack
- Speed
What are the best Honkai Star Rail Dr Ratio team comps?
First things first in a Dr. Ratio team – debuffers. As many characters capable of debuffing enemies as possible. You can also use Yukong to improve Dr. Ratio’s damage. A healer like Luocha or Huohuo or a shielder will also come in handy, as Dr. Ratio has no way of healing or protecting himself.
You can use Nihility characters like Kafka, Luka, Guinaifen, and Sampo to apply even more debuffs through their damage-over-time skills, but the best debuffer is Silver Wolf by a mile.
| First character slot | Second character slot | Third character slot | Fourth character slot |
 Dr. Ratio |
 Topaz |
 Pela |
Flexible healer slot |
| Dr. Ratio |
 Yukong |
 Welt |
Flexible healer slot |
| Dr. Ratio |
 Luka |
Pela |
Flexible healer slot |
| Dr. Ratio |
 Silver Wolf |
 Bronya |
Flexible healer slot |
What are Dr. Ratio’s abilities?
Dr. Ratio focuses on single-target damage and has a hefty follow-up attack in his kit. He can dish out plenty of imaginary damage despite being limited to single-target moves. Here are all the different things he can do on the field:
Active skills:
| Skill | Effect |
| Basic attack: Mind is Might | Dr. Ratio uses his codex to deal imaginary damage to a single target equal to 90% of his attack |
| Skill: Intellectual Midwifery | Deals imaginary damage equal to 131% of Dr. Ratio’s attack to a single target enemy |
| Ultimate: Syllogistic Paradox | Dr Ratio deals imaginary damage equal to 216% of his attack to a single target and applies Wiseman’s Folly. When his allies attack a target marked with Wiseman’s Folly, Dr Ratio launches a follow-up attack one time against the target. Wiseman’s Folly can trigger twice and only affects the most recent target. This trigger count resets when using his ultimate |
Talent:
| Skill | Effect |
| Cogito Ergo Sum | When using his skill, Dr. Ratio has a 40% fixed chance of launching his follow-up attack against his target one time, dealing imaginary damage equal to 236% of his attack. For each debuff the target enemy has, the fixed chance rises by 20%. If the target enemy gets defeated before the follow-up attack triggers, the follow-up gets directed at a random enemy instead |
Technique:
| Technique | Effect |
| Mold of Idolatry | When using his technique, Dr Ratio plants a stone statue that creates a dimension, taunting nearby enemies. This lasts for ten seconds. After entering battles with taunted enemies, there is a 100% base chance to reduce each single enemy’s speed by 15% for two turns. Only one dimension can exist at a time |
Traces:
| Trace | Effect |
| Summation | When Dr. Ratio uses his skill, for every debuff on the target, his crit rate increases by 2.5% and crit damage by 5%. This can stack up to six times |
| Inference | When his skill attacks an enemy target, there is a 100% base chance to reduce the attacked target’s effect resistance by 10% for two turns |
| Deduction | When dealing damage to a target with three or more debuffs, for each debuff the target has, Dr Ratio’s damage increases 10%, up to a maximum of 50% |
What are Dr Ratio’s eidolons?
We all got our first Dr. Ratio free in the mail, so there’s nothing stopping us from getting some eidolons during his banner. Here’s what each of them unlocks.
| Eidolon | Effect |
| E1 – Pride Comes Before a Fall | The maximum stackable count for the trace ‘Summation’ increases by four. When a battle begins, Dr. Ratio immediately gains four stacks of Summation |
| E2 – The Divine is in the Details | When Dr Ratio’s talent follow-up attack hits a target, for every debuff the target has, he additionally deals Imaginary damage equal to 20% of his attack. This can trigger four times during each follow-up attack |
| E3 – Know Thyself | Increases Dr Ratio’s ultimate level by two, up to a maximum of 15. Increases his talent level by one, up to a maximum of ten |
| E4 – Ignorance is Blight | When triggering his talent, Dr. Ratio additionally regenerates 15 energy |
| E5 – Sic Itur Ad Astra | Increases Dr Ratio’s skill level by two, up to a maximum of 15. Increases his talent level by two, up to a maximum of 15 |
| E6 – Vincit Omnia Veritas | Additionally, it increases the triggerable count for Wiseman’s Folly by one. The damage dealt by the talent’s follow-up attack increases by 50% |
What are Dr Ratio’s ascension materials?
To get Dr. Ratio leveled up nice and quick, here is a simple list of materials you need to ascend him through each level.
| Required level | Credits | Materials |
| 20 | 4k | Five thief’s instinct |
| 30 | 8k | Ten thief’s instinct |
| 40 | 16k | Three suppressing edict and six usurper’s scheme |
| 50 | 40k | Seven suppressing edict and nine usurper’s scheme |
| 60 | 80k | 20 suppressing edict and six conqueror’s will |
| 70 | 160k | 35 suppressing edict and nine conqueror’s will |
What are Dr Ratio’s talent materials?
Improving Dr. Ratio’s damage is key, and to do that, upgrading all his talents is what you’re gonna need to do. Here’s the list of materials you need, and how much money it costs to get his talents from level one all the way to ten.
- 41 thief’s instincts, 56 usurper’s schemes, and 58 conqueror’s wills
- Obtain from synthesis, voidranger enemies, and simulated universe enemies
- 15 arrows of the beast hunter, 72 arrows of the demon slayer, and 139 arrows of the starchaser
- Obtain from the Bud of the Hunt crimson calyx in the outlying snow plains, synthesis, and the embers exchange
- 12 past evils of the borehole planet disaster
- Obtain from the Starcrusher swarm king (Skaracabaz) boss in the Seclusion Zone on the Herta Space Station
- 11 tracks of destiny
- Three million credits
Skill trace priority:
Talent > ultimate > skill > basic attack
Major trace priority:
Summation > Inference >Deduction
That’s all we know about Dr. Ratio so far, so why not brush up on some other builds? We’ve got guides for Honkai Star Rail’s Argenti, Honkai Star Rail’s Huohuo, and Honkai Star Rail’s Hanya to ensure you get the right relics and light cones on each character.