Nihilak's eyes widened as he witnessed Venganza merging with Zatiel, causing this one's aura to ascend steadily. The Knight had meticulously studied his adversaries and was aware of Zatiel's Three Samsara Incarnation. Two of them had already fused with the Samsara Thearch, but the third, the Soul Depravita Incarnation, had gained his own ego and was reborn as the Depravita known as Venganza.
If Venganza were to simply merge with the Samsara Thearch, the enhancement to his power would not be extraordinary, and it wouldn't significantly bolster his combat capabilities. The reason was straightforward: Zatiel's soul force was already breaking the limits of the Middle Stage, and a fusion with Venganza would be imperfect since this one possessed his own distinct identity.
