What has two thumbs and killed the two defenders in successive rounds? This guy:
One of my players challenged me to come up with an epic-tier solo boss that was truly solo. This was the result. I make no bones about the fact that I ladled on a truckload of anti-effect powers. I was also trying to establish that the epic tier was going to feel a little bit different than the paragon tier. Bad things are going to happen more often. I’m sorry if the following is too “mathy” and technical. A good GM can create story around any monster or NPC, but that’s separate from learning how to balance a complex design.
As with every monster that has a “minigame”, there were a number of design questions. The first was whether or not Berzerk had to be an encounter power with no possibility of recharge. My theory was that Berzerk would be best when it hit eight or nine rage. This would provide a rage dump to prevent Tantrum from getting too large, while still keeping a level of threat. If it starts taking three or four turns a round, however, the encounter could spiral out of control.
During the actual running, Gutbuster read “Free Action, 1/turn; Spend 1 rage: Y’gal’s attacks do +2d10 damage until the start of its next turn.” I had expected that Y’gal would hover at 3-5 rage until one of the larger rage gains triggered, most likely the one for becoming bloodied. It would then activate Berzerk, bringing it back down to 3-5. In this way, Gutbuster would always remain a meaningful question – Is +2d10 damage worth an extra attack? As Slam averages out to 32 damage, Gutbuster is only a net gain if it hits with three or more attacks. Against a high-AC target, more attacks is better, whereas Y’gal can just mulch a softer target.
This created a pleasing mechanical tension where the defender(s) felt good about keeping the monster’s attention. Every time Y’gal turned on one of the other characters, the defenders were quick to punish it. Forced movement became key.
The problem arose when Y’gal missed all its attacks, going to 6 rage. This would have been manageable, except that the Rogue hit it with a critical and was bloodied by Lash Out. Suddenly at 10 rage, there was absolutely no reason to not activate Gutbuster. The Paladin recognized the danger and pulled the monster over into the corner so that it could only attack her. While this worked out great for protecting the rest of the party, it exposed her to 9 boosted attacks. She went from barely hurt to dead in a single turn, preventing the Cleric from being able to respond. The Fighter rushed in and Y’gal repeated the process its next turn, taking him from unhurt +15 temporary hit points to dead, despite jacking his AC to 43. (To be fair, I did crit twice during that series. I needed a 14 to hit him. Had the rolls been more average, he definitely would have survived.)
This revealed the main mechanical fault: once Y’gal reaches “critical mass”, it’s going to pretty much kill a character a turn. To my players’ credit, they dug in when they realized this. The Cleric actually said, “We’re going to sacrifice one of us at a time until it’s dead or we are.” They were able to drop the monster just before it fixed itself a bowl of Rogue Chow. So, yes, the fight is on a clock, but it’s not a fun clock, at least not for my table.
So we need a good reason to bleed off rage so that Tantrum doesn’t get too out of hand. It’s possible that other parties might have more abilities that would make the monster want to use Burning Fury but not trigger Obyrith Unshackled (As an aside, the obyriths in my home campaign are aberrant creatures that can infect elementals, but are not themselves elementals. You might want to change the keywords accordingly for other settings. In a more canon environment, Y’gal would be a Huge Elemental Humanoid.) This version of Gutbuster is intended to meet that need. I don’t know if it changes the “correct” play to something that’s more fun, but it certainly gives the GM a tight tuning knob for the number of attacks and amount of damage.