When their blades met, the Fomor needed to give everything he had to not be sent flying away due to the abyssal gap in raw strength between them. Eryon used the power of the earth element to become heavier and resistant to harm.
The air element to increase all of his abilities threefold and the fire element to engulf his body and equipment in mystical flames that ate at both the mana and equipment of his opponent.
"You know, this would have been much more impressive if your bloodline abilities weren't half-baked and I hadn't fought against Thrud's generals until I got sick of it!" Lith infused War with a spark of Chaos, turning it black as Origin Flames burst out of his scales.
The violet-black flames easily overpowered the Fomor's while the angry blade cut through his defensive orange aura. Even though Eryon's eyes granted him mastery over the six elements and several powerful abilities, it wasn't enough to stand against the Tiamat.