Antagonist
Character Role Analysis
The World
There are a bunch of baddies in Candide: the Bulgars who conscript Candide into the army, the Inquisitor, and the Governor.
But the closest thing to a single antagonist in Candide is the world itself. The world of Candide is one of suffering, misfortune, and pain (think shipwrecks, miserable coincidences, and a massive earthquake). It is the world at large that Candide battles in both the specific challenges he encounters and his greater battle for happiness and philosophical understanding.