by Mike Shea on 10 September 2012
In July 2012, Wizards of the Coast published my D&D Insider adventure The Sword Collector. This short adventure includes a double-length encounter focused on the mushroom pool map included in the Vaults of the Underdark map pack, a product I highly recommend you include in your encounter map portfolio. Note, the Sword Collector article requires a DDI subscription. Today we're going to discuss some of the design decisions behind the Sword Collector with the intent of giving you some tips and tricks for developing your own large set-piece epic-tier encounters.
The Sword Collector was designed as a single setting double-length encounter. Double-length encounters are one way to bring a good deal of threat to an epic-tier party. It forces them to conserve their resources across both battles or, should they not realize it is a double-length encounter, they might spend resources up front and struggle through the second half of the battle. Generally speaking, I would make it clear to the party that they may want to hang onto vital resources, like healing, later into the battle.
Still, every time I've worried about wiping out an epic-tier party, I saw all new creative ways for them to get out of danger.
The adventure begins with an elite and three normal monsters, the balhannoth has some interesting epic-level effects such as an anti-magic field and a reality distortion that gives it teleportation and invisibility as a move action.
The key to an exciting multi-stage encounter is changing the variables of the battle during the fights. For example, the poison mushroom hazard in this adventure takes place only once the balhannoth is killed.
All good 4e battles need some sort of early combat out; a way for a battle to end early without requiring that the PCs defeat every monster on the opposing side. With a double-length encounter, this is also important. There are two combat out's built into the first wave of the encounter. First, the balhannoth psychically controls the hook horrors. Should the balhannoth die, the hook horrors will regain control of their faculties and flee the chamber. The second out takes place when the balhannoth is first bloodied. While bloodied, the hook horrors' defenses drop by two and they gain +10 damage. If the hook horrors start to get killed, the balhannoth likewise loses defenses but gains damage output. For a little extra challenge, I'd increase his bonus damage to 10 instead of 5.
This gives us outs for multiple outcomes. Should the PCs go after the hook horrors, the balhannoth becomes easier to kill but more dangerous when it attacks. Likewise for the hook horrors. Whatever path the PCs choose, the battle will escalate as it goes on.
Likewise, in the second wave, everything depends on killing the sword collector. The bulette, while dangerous, doesn't actually need to be killed to succeed in the adventure. There isn't a skill check in the adventure for it, but I'd give those trained in nature and perception a chance to detect this as the battle gets longer.
The Sword Collector is the only published D&D monster I know that includes direct immunities to daze, dominate, immobilize, restrain, stun, and weaken. I like transforming these normally debilitating status effects into direct combat advantage. I think the Arcane Harmonics power would make a good addition to many boss monsters, though I would likely group movement impairment and action impairment into separate categories and change the effect reduction accordingly. For example, any movement impairment might instead result in -2 to speed. Any action impairment might instead result in -2 to defenses and vulnerable 5 per tier to damage.
I'm guessing players will get mad the first time they discover this effect reduction. Blame me when they yell at you. I'd also make it clear to players that their status-effect-laden powers would work better on the bullete than the sword collector.
The dancing sword is a nice hazard since it acts like a monster but cannot be affected like one. PCs have to use skills to interact with the sword while it whizzes around the battle field cutting into folks. I might increase its movement to 12 squares if you want the extra challenge.
I think it's important that we escalate the threat in battles like this so they don't become a drag the minute the PCs get the upper hand, which, at the epic tier, happens quite early in most battles. The poisonous mushrooms are the big escalator in this battle. Each round they increase their damage so three or four rounds in they're pouring out 30 poison damage to every PC in the room. This has a nice effect of forcing the players to focus their energy on defeating the challenge.
The Sword Collector has some good challenges for epic-tier PCs, but if your group is particularly powerful, consider these Sword Collector Nightmare Mode challenges:
Again, players are likely to call bullshit on some of these effects. Shrug and blame me or remind them that epic PCs face epic threats to receive their epic rewards. Don't screw them over by making them blow abilities, but make it clear those abilities won't affect the Sword Collector itself.