The Domains Merged, It's Ineffective?
William and Uri competed back and forth with Supreme Left and Unbreakable Right in a battle of wits and attrition, each pair using multi-layered schemes to waste the other party's Mana more efficiency.
Spirit Auras were raised, Forcefields recovered and shattered again, and dozens of Spells cast in a period of just a few minutes. The moves alternated erratically between extreme quantity and great quality, dozens of Fireballs cast by Supreme Left countered by oceans of William's Water Mana, only to be redirected with a simple Earth Wall from Unbreakable Right.
It had become a stalemate through and through, but William could sense that he was on the back foot. Uri was powerful, but his Mana Reserves weren't as profound as the two legendary Cultivators and he was slowly losing steam.