How-To DM: Building Encounters (Part 2)

Hello Everyone and welcome! Last week we discussed one philosophy behind building encounters. Today, I’d like to talk about some practical mechanics behind implementing those philosophies into a game.

For our purposes here, let’s assume a party of 5 4th level characters: a Goblin Totem Barbarian, a Human Moon Druid, a Human TWF Ranger, a Tabaxi Archer Ranger, and a Human Archer Fighter.

They have unwittingly wandered into a kobold complex, and I want to really challenge the Druid and Barbarian with the very real possibility of death without instantly dooming the rest of the party.

So let’s talk about tips on the mechanics of building encounters in this week’s How To DM!

Don’t Trust the Challenge Ratings (CR): I find CRs only marginally useful because they are a limited tool at best. A creature’s CR just can’t account for things like a party’s use of tactics or spell selection or the effects of terrain. CRs also don’t reflect a party’s ability to capitalize on things you didn’t consider in your design or a mistake in your placement of bad guys. I’ve had groups waltz through “deadly” encounters with barely a scratch only to lose several members to an “easy encounter” later on.

Determine the Total HP of the Party and the Opposition: I always start here because the results can be deceptive. On paper, the party has 142 total HP on paper. However, the barbarian effectively has double his HP due to damage resistances, so that brings the total to 187. The Moon Druid likes the Dire Wolf shape right now. With two Wild Shapes, he can add as much as 74 more HP to the group, so now we’re at a whopping 261 group HP!

Considering that the average kobold has 5 HP…that’s 52 Kobolds just to equal the party’s effective HP in one fight!

Consider the Action Economy: I always compare the party’s action economy to their enemies. The party can put out 7 attacks a round (if the TWF Ranger can use Horde Breaker).

The kobolds? 52. Even if you send them in waves, that’s a lot of Kobolds!

Determine Damage Output: Enemy AC isn’t normally a factor for me; I just calculate maximum damage and assume all attacks hit. Now that equals an average damage of around 50 points a round, but any damage output over 35 points is wasted because Kobolds only have 5 HP each.

But the Kobolds have 52 attacks, at 4 damage each. But Pack Tactics gives each Kobold advantage as long as an ally is within 5’ of the target. That’s potentially 208 average damage a round once the kobolds swarm over them. Even at half that damage rate, the party has maybe 3 rounds before they’re wiped out.

Conclusion? Now we have a clearer picture of what each side brings to the table.

In a straight up fight – with the Kobolds fighting with even minimal brains – the party is doomed to death from the beginning. Mechanically, they really have no way to win.

But, sending them in in waves of 10 is no challenge at all, and waves of 20 will maybe challenge the Druid and Barbarian somewhat with the very real possibility of killing some of the other party members.

So, what can we do with this mess? How do we construct this encounter to be both challenging and fair for all our players?

Come and see us again next week when we talk about Including Victory Conditions into our encounters and how to balance combat with Terrain and Targeting. What tips, tricks and advice do you folks have? Put them in the comments below, so we can all share in the info.

Thanks for reading, and we’ll see you next week for another installment on How To DM!

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