Grim Dawn Grim Misadventures #69

The 69th "Grim Misadventures" feature over on the Grim Dawn forums shares some interesting information about how the game's factions will react to us after we've slain a significant number of their members, and the rewards we will be able to reap (along with the pain we'll suffer) when a Nemesis boss shows up to takes its revenge over our incessant killing. Treasures await:

Despised Status
At the first tier of infamy, you will begin to see additional champion spawns, sometimes that will include monsters that do not normally spawn in an area appearing to bolster their forces, such as more powerful chthonic beings around cultist camps.

This is just the beginning on the road to becoming a faction's Nemesis though.

Hated Status
Upon reaching Hated Status, the faction knows that you are not someone to be trifled with. You will begin to see an increased rate of Hero Monster spawns for that faction wherever you may find their forces. In the case of Kymon's Chosen and the Order of Death's Vigil, this will be the first time you even encounter their heroes.

Nemesis Status
Nemesis tier represents the pinnacle for hostile factions. This is when you have angered the group to the point where the gloves come off, no more holding back. This is when you will begin to see Nemesis spawns.

Nemesis spawns are ultra-bosses, some of the toughest encounters you will face in Grim Dawn, and they have a chance to appear in just about any area where their faction is present. Should you encounter one, do not try to flee; it is already too late. A Nemesis spawn will pursue you far beyond the leash range of regular monsters. And when you inevitably die a painful death, the Nemesis will feast upon your wretched remains, regaining some of its lost vitality in the process.

Should you somehow prevail, vast riches await you within the Nemesis Chest, with a guaranteed Epic item and, in the future, an increased chance of finding Legendary items.