Antithetical Complex Essences

From Wydd's Wiki

When casting a spell using Complex Mana Type/Deep Dominion Essences and one of it's Antithetical Essences, the spell will be much more difficult to cast and control. Each Prime/Base essence type and the Deep Dominion/Complex Mana type page contains information on the Antithetical Prime Essences associated with that essence type.

A complex mana type is antithetical to another complex mana type when both component prime mana types are also antithetical.