The God of War was losing, badly, according to all mortal standards. Yet the battles between immortals were quite different from mortals. They used their greatest weapon during their battles which was time to maneuver their way through a conflict.
A battle between gods was not fought in hours, days, or weeks, their battle was fought across eons.
Rowan was a terrifying being in the sense that every Immortal battle he had fought had always been quite short. He had all the traits of a God-Killer, and he had never truly had any reason to fight a protracted battle, as he could reach the core of any god which was their soul, disregarding their bodies.
This was the greatest advantage of an Immortal Soul, which was the ability to create as many bodies as they wanted while keeping their core safe using nothing but Divine Energy.