Hearts of Darkness are evil gemstones created by Ebonscale that drain the power of malicious beings who ally with him - effectively destroying them as their essences become imprisoned within the gemstones, which Ebonscale would proceed to devour in order to grow in power.

As part of the central theme of Monsters heroes and villains must decide whether to continue fighting one another or ally temporarily as a matter of survival..

Inferno is especially aware of this plan due to his link to Ebonscale and has already began to formulate a plan - though its ultimate success is still to be determined..