Rin Tohsaka is a 5-star Quantum character on the Path of Erudition, and like every other unit in Honkai: Star Rail, she carries six Eidolons that you unlock by pulling duplicate copies. Two of those Eidolons, E3 and E5, only raise her ability levels, so the ones worth debating are E1, E2, E4, and E6. Each of those changes how her Gem Energy engine and Skill damage behave, and they are not equal in value. Below is where each one lands and why.
Quick answer: E1 (Zelretch’s Apprentice) is the standout copy and the one to prioritize before her signature Light Cone; E6 and E2 are strong but costly, and E4 is skippable unless you are going for the full set.
Rin Tohsaka Eidolon tier ranking
| Tier | Eidolon |
|---|---|
| S (get it first) | E1 — Zelretch’s Apprentice |
| A (strong, but expensive) | E6 — Nailed It This Time! |
| B (situational) | E2 — Dimensional Traveler |
| C (skip unless completionist) | E4 — Red Devil: Triple Speed |
This ranking weighs each Eidolon by the damage it adds relative to how many pulls it costs, and by whether it helps in both of Rin’s roles, as an Archer support and as a solo main DPS. Copies that only pay off in one narrow setup rank lower.
E1 — Zelretch’s Apprentice
This is the best copy to chase. If a single Enhanced Skill (Second Magic Experiment) burns 30 or more Gem Energy, Rin banks that amount as “Shadow Gem.” While she holds Shadow Gem, her Skill stays enhanced, and the next Enhanced Skill spends the Shadow Gem instead. That version does not convert Skill Points into Gem Energy and does not consume regular Gem Energy at all.
In practice, it hands her a second high-multiplier nuke that costs no resources. It works cleanly whether you run her as a sub-DPS beside Archer or vertically as a main DPS, which is why it earns the top spot and why it is usually worth prioritizing over her Light Cone.
E6 — Nailed It This Time!
Her sixth Eidolon is a heavy hitter. It grants a flat 20% All-Type RES PEN, and every time she casts her Ultimate she gains 24 Gem Energy plus one extra turn. Since she needs 15 Gem Energy to keep her Skill enhanced, that Ultimate refund immediately powers her next Enhanced Skill, and the extra turn stacks even more damage on top.
The payoff is real, but it sits at the very end of the Eidolon path, so the pull cost is the only thing holding it back. If you have the Stellar Jade to commit to the full set, this is the reward that makes it feel worth it.
E2 — Dimensional Traveler
E2 raises Rin’s own Skill damage by 30% and makes all allies’ Skill damage become 130% of the original while she is on the field. On paper that reads like a big number, and for a main DPS build it does pull real weight.
The catch is the pairing that most players actually run. In a dual-DPS setup with Archer, much of his output comes through his Ultimate and the shared Joint Follow-Up ATK rather than his Skill, so the ally-wide Skill boost does less than the headline suggests. That is why it lands in the middle instead of near the top, even though some setups value it very highly.
E4 — Red Devil: Triple Speed
E4 lets the CRIT DMG buff from her Talent, Gem Magecraft, stack on Rin herself up to two times. The base buff is 70% CRIT DMG for two turns whenever an ally consumes or recovers a Skill Point, so this doubling does add a decent chunk of personal damage.
Even so, it is the weakest of the four for the pulls it demands. Unless you are already committed to grabbing every Eidolon, this is the one to pass on.
How to read this ranking
Because each Eidolon requires another full copy of a limited 5-star, most players will only ever unlock one or two. If you are buying in, E1 gives the cleanest return in every team she fits. E6 is the target for anyone going all the way, E2 is a judgment call based on whether you lean into her own Skill damage, and E4 rounds out the set without changing much.
This ranking reflects Rin Tohsaka’s kit as it stands in Version 4.4. Her strongest home remains a team built around Archer, where her Skill Point generation and shared buffs matter most, but E1 keeps her flexible enough to carry as a main DPS when you want to build vertically.
