Arther staggered back with wide eyes. He couldn't believe someone could shatter his Sphere of Aegis. Normally, opponents would have to wait until the skill ran out of its duration.
Jack was honestly also surprised, but he didn't waste time wondering about it. Once the protective sphere around Arther was gone, he shouted, "Now!"
Jack didn't truly need to shout the signal, he just did it out of instinct. He used his mind to synchronize with his spirit weapon and Therras.
Therras used its Imperious Pressure to slow Arther's combat clone down as earth mana accumulated in his mouth. Jack used Mirage Beast to create a copy of Therras and have it keep the combat clone busy. The spirit weapon meanwhile rushed to Arther and activated its finishing mode.
Jack used Gold Dragon Breath when Arther was still shocked about Jack breaking his Sphere of Aegis. The breath triggered Blind as well as reduced the durability of Arther's armor.