An Elden Ring player has found out that using a holy infusion on the Black Steel Greatshield gives it 100% holy damage negation, something that wasn't possible all this while in the game. This can be a huge gamechanger for a lot of boss battles, like the Elden Beast as well as the final boss in Elden Ring Shadow of the Erdtree DLC, as holy damage has been quite frustrating to deal with for players.