Every Magic card has either no mana cost or exactly one mana cost. A card with no mana cost is never counted by Embodiment of Agonies. A card with a mana cost of {0} is counted.

Embodiment of Agonies checks the mana symbols in a card's mana cost. For example, a mana cost of {X} is different than a mana cost of {0}.

Hybrid mana symbols are treated as the actual symbols, not as either of their two components individually. For example, {B/R}, {B}, and {R} are three different mana costs.

The mana cost of a split card is determined by its two halves combined. For example, the mana cost of Fire//Ice in your graveyard is {2}{U}{R}, the same as the mana cost of Ral's Outburst.

Alternative costs, additional costs you could pay, cost increases, and cost reductions are all ignored by Embodiment of Agonies.

If you return Embodiment of Agonies from your graveyard to the battlefield, its last ability counts itself.