Passkey
Passkey is a 3★ Light Cone for the Path of Erudition in Honkai: Star Rail.
As a 3-star cone its base stats are low, but the 8 Energy regen on Skill use is genuinely useful for Erudition (Mage) characters wanting faster Ultimates, making it a solid early-game filler.
After the wearer uses their Skill, additionally regenerates 8 Energy. This effect cannot be repeatedly triggered in a single turn.
A drop of strength condensed from time itself. All the seemingly insignificant moments come together to form the magnificent choir of fate. "Knowledge is locked behind a gate, the key to which is hidden from those seeking answers from others, while made obvious for those determined to find it on their own."
How to read this Light Cone page
Every Light Cone has exactly one passive effect tied to the wielder's combat performance; that effect scales up as you Superimpose it from S1 to S5 — use the S1-S5 buttons above to see the exact numbers at each level instead of guessing or interpolating. A Light Cone only delivers its full value on a character who shares its Path; "Characters who use this cone" lists every character on that Path, while "Best users" is a narrower list pulled from real build consensus, not a guess.
Base stats (HP/ATK/DEF) are shown at Lv80 for every cone of the same rarity so they can be compared directly; a 5-star cone will always edge out 4-star and 3-star ones here — the real difference lives in the passive effect, not the flat stats. The "Alternative cones on the same Path" section suggests a few other options if you do not own the signature cone yet, or want to compare before spending ascension materials.
See the full list on the Light Cones page, or check terms in the HSR Glossary.