Deadlands/YMMV

Character Tiers: There are no levels, so the Marshall is on his own when it comes to scaling opponents to the levels. All of the major villains also form a God Tier. They originally didn't even have stats, and even when they were eventually statted they all have indestructable Plot Armor.
Complete Monster: Stone and Raven. Grimme can be considered one too, although he is more of an Humanoid Abomination.