Overview

Abyssalcraft currently induces both temporary and permanent Warp when:

• Hitting any hostile mob from the mod, including Demonic Livestock, Shoggoths, Shadow Creatures, Coralium-Plagued Zombies and Depths Ghouls. All of these can be found without ever involving one's self in the mod properly.
• Getting hit by any hostile mob from the mod
• Spending time anywhere in the Abyss
• Crafting and upgrading the Necronomicon

This Warp is part of Abyssalcraft's integration with Thaumcraft, which also adds two essential types among other things. Thematically, this makes sense: Abyssalcraft is all about Lovecraftian, unfathomable horrors, and Warp acts as a good surrogate mechanic to express the tolls that horrors take on the mind.

Why care?

The Warp these activities bestow is significant. Just be hunting Shadow creatures and shoggoth lairs to even begin exploring the mod's dimensions, I gathered enough temporary warp at a time to trigger serious Warp events, like Sun Scorn and Eldritch Guardians. Unless the player wants to be subject to the full effects of Warp constantly without reaping any of the benefits, they are forced to do significant amounts of Thaumcraft - an unrelated mod - until they can fight Warp and its effects.
A player should not be required to develop in an unrelated mod to experience another in a Kitchen Sink pack like ATM 3. An inexperienced player may not even know that Thaumcraft is the mod the Warp messages come from, and be completely subject to it while they explore the cool Lovecraft mod.

Suggested fixes

• Tone down the numbers

  It's not inherently bad that the mod introduces mental strain on the player, due to thematic consistency. As it stands, however, it is far too much and far too punishing, practically necessitating Thaumcraft infrastructure for even engaging with overworld mobs. This depends on how flexible the config is, and it may be possible only to lower the Warp dealt by all Abyssalcraft sources.

• Remove some Warp sources

  This is also dependant on config flexibility. Currently, the Abyss isn't a threatening place with sufficient gear, and Warp could be a way to punish players that decide to loiter in places they were never meant to be. This suggestion, and the one I am most in favour of, involves removing Warp effects from Mobs, but keeping the ones for loitering in dimensions and upgrading the Necronomicon. The former should issue enough temporary warp for it to rise while one remains in the dimension, and the latter should bestow enough permanent warp to be a nuisance without being threatening.
  This way, players that don't wish to go through Abyssalcraft don't have to be punished by its mechanics for remaining in the overworld, but players that do engage feel some thematic immersion.
  If this is the route taken, it may also be worth adding a tooltip to the Gateway keys or the Necronomicon alluding to the soothing of Warp through Thaumcraft.

• Remove the Warp mechanics entirely

  Thaumcraft is unrelated from Abyssalcraft, and there's a valid argument that the mods shouldn't overlap in a Kitchen Sink pack like ATM3. This will almost certainly be possible in config.