The new Pestilence skill has both advantages and disadvantages. It spreads to an entire group almost instantly, and few can resist it, but unlike poison it doesn't stack.
Secondarily, it's a passive, so if you're looking to assassinate a target without alerting those around them, it's not happening. Unless those people are not allies with them or enemies to you.
In their current situation Pestilence is amazing, and Cain can't wait to try it out inside the Beastkin dungeon where everything crowds around them by the entry.
Unlike the early day they had planned, the raid ends up grinding late into the afternoon, as a few members were very close to hitting level 80. After that the experience per level is insane, level 75 to 80 takes the same as 80 to 81. No wonder everyone gets stuck at or near level 80 in the valley. Even in the Demon Raid, the toughest fights they've seen so far, and with Cain's experience bonus it's still going to take multiple days per level.
