Melee combat strategy
Given that the Godskin Apostle boss is prone to bleeding, both kinds will profit tremendously from a disorderly hand-to-hand encounter, particularly if hit with a bleeding-causing weapon. As more blood is drained from him, he grows weaker.
Whenever the boss attacks, attempt to land a couple of dual hits. Furthermore, inviting additional players with the ability to use bleed weapons will increase the blood to collect faster.
Ranged combat strategy
You can either cheese the Godskin Apostle boss by employing a ranged attack or spam different sorceries at him until he dies. If you are worn out from the battle and have faced him multiple times, you can go for the cheese. Comet Azur in the Elden Ring will be required for this (Sorcery). Both the encounter in Windmill Village and the subsequent encounter with Caelid can be resolved using the sorcery you learn on the Atlas Plateau. Cerulean Hidden Tear should be poured into your Wondrous Flask and consumed when the combat begins. After calling any Spirit Ash, you can briefly tank the boss. The boss' health bar can be completely destroyed by Comet Azur when used with the Hidden Tear for more than ten seconds.