Having eliminated fire and water as viable attack options, since both would just feed the serpent's reserves, he evaluated the remaining elements the Wolverine had available.
Earth seemed the most promising option.
It had no inherent weakness to fire or water... Wind and wood would then be weak too.
Earth versus the dual water-fire system seemed to have no obvious interaction disadvantage. Earth was just... Neutral.
Solid. It didn't burn easily, didn't dissolve easily. It just was.
And that neutrality was exactly what made it effective. The serpent's sophisticated elemental balance system had no special mechanisms for handling earth-based attacks beyond the standard options any Gold 1 beast possessed.
Light and darkness could serve as well. They operated in a different spectrum from the thermal and fluid interactions water and fire dominated. But they were slightly more expensive in mana terms for comparable effectiveness.
