Diablo 4's newest endgame activity, Infernal Hordes, will be playable during the Season 5 PTR. Similar to how players can augment the challenge of Helltides with the Profane Mindcage Elixir, the difficulty of this wave-based survival mode is also able to be enhanced through Abyssal Scrolls, which are similar to Nightmare Sigils.
Infernal Horde New Endgame Mode in Diablo 4 Season 5
We have found the following items that appear to increase player power when fighting through the waves of Infernal Hordes.
It appears these Anointments can also be crafted!
Not much is known about this new consumable type, other than what's listed in the tooltips — along with the fact we will likely be receiving these caches from Side Quests and other sources. So, we'll have to wait and see whether using their Anointments comes at a cost!