Learn French: Quand bien même il serait invincible, le super-héros pourrait perdre. - Even if he were invincible, the superhero could lose.

Unlike même si (even if), which requires the imperfect tense to express a hypothesis (like même s'il était invincible), the phrase quand bien même is always followed by the conditional. It is a more formal way to express a strong hypothesis or extreme concession.

Both halves of this sentence use the conditional (serait and pourrait). Is this normal?

Yes! Because quand bien même sets up a hypothetical situation in the conditional, the main clause describing the consequence of that hypothesis naturally takes the conditional as well. It works just like the "result" half of an English "if... then..." sentence.

Could I drop the bien and just use quand même at the start of the sentence?

No, they have different grammatical roles. Quand bien même means "even if" and introduces a hypothetical clause. Quand même means "anyway" or "all the same" and acts as an adverb, usually placed after the verb (e.g., Il pourrait perdre quand même - He could lose anyway).

Why does super-héros end in an "s" when the sentence is about a single superhero?