The Apostle will, at range, throw Blackflame at you, knocking you to the ground should it make contact. These can be easily dodge-rolled so long as you keep an eye on the Apostle at all times, otherwise this will catch you out and leave you vulnerable to a follow-up attack.
As a melee fighter, the Apostle is incredibly aggressive. The Apostle can perform jabs with the lower end of its staff but mainly relies on fast flurries and combos. It spins staff furiously in front of itself, creating a whirlwind-type effect that is recommended that you just run away from. It will also perform multiple 360-degree spins often ending in an overhead jumping slam. All of these attacks are best dodged, as the ferocity of the attacks can make it incredibly risky to attempt a parry.
At around 50% health, the Apostle will float off the ground and hunch up before exploding out in a Blackflame sphere. This initiates the second phase of the encounter, where the Apostle becomes even more aggressive and speedy. It also has the ability to extend its body to cross the entire distance of the arena, performing variations of sweeps, slams, and slashes but aren't restricted to the Apostle's immediate vicinity. The best way to make this encounter far easier, like other boss fights, is to use the Mimic Tear Ashes. That allows the Apostle to focus many of its attacks on the Mimic, which makes it easier to execute jumping attacks that can stagger the Apostle opening it up to critical strikes.
Upon defeating the Godskin Apostle, you'll earn the Godskin Apostle Hood, the Godskin Apostle Robe, the Godskin Apostle Bracelets, and the Godskin Apostle Trousers. If you head down the steps on the opposite side of the arena to where you entered, you'll find a wisp of light to teleport you outside the tower, alongside a chest that contains the Godslayer's Greatsword.
