In the recent V1.0.0.3 patch for Grim Dawn, developer Crate has stealthily added a set of official modding tools for enterprising community members who wish to make their own content. Described (and revealed) via the Grim Dawn forums, these tools are the exact same programs used by the devs themselves and allow for creation of not just new items or monsters, but entirely new campaigns as well.

The tools, along with a guide on how to use them, can be found within your installation folder after the update has completed. Crate has also made the guide available on their website, which can be downloaded manually here.

The patch also comes with a few fixes, the most notable of which being that celestial skill activation rates are now governed by the cooldown length of the attack they are pinned to. This now means that attacks with longer cooldowns will now benefit from having higher celestial skill activation rates.