Encounter Design: “Bleeding Blades” — A Survival Gauntlet in the Sea of Blades

Encounter Design: “Bleeding Blades” — A Survival Gauntlet in the Sea of Blades

July 7, 2025

💀 Terrain as Weapon: The Deadly Plains of the West

Welcome to the Sea of Blades—an ocean of tall grass that cuts like steel. This isn’t your average field; here, each swaying stalk is a blade that can flay the flesh from bone. Thri-kreen prowl these wilds, but even they tread carefully.

In this encounter, we’re leaning into the terrain as the enemy. The party is traveling on foot or trike through the Sea of Blades on a crystal scavenging mission—or maybe they’re tracking rumors of a ‘kreen warband amassing near a shardstorm. Either way, survival will depend on wit, endurance, and how much skin they can afford to lose. Check out more Under the Dome here.

⚔️ Encounter: “Bleeding Blades”

Level Range: 8–12
Location: Central Sea of Blades, 10 miles west of Blade Gate
Tags: Environmental Hazard, Survival Challenge, Ambush

🧾 Setup

The party is traveling across the tallgrass. Each “turn” of movement requires navigation through grass that acts like serrated metal.
They’re being shadowed by a Thri-kreen pack—including an Alpha that understands terrain warfare.

The party has two goals:

Survive long enough to reach the crystal-strewn rise 300 feet ahead.
Evade or confront the Thri-kreen ambushers.

🌾 Terrain Mechanics

Cutting Grass (Hazard, Constant)

At the start of each creature’s turn in the tallgrass, they must make a DC 14 Dexterity saving throw or take 2d6 slashing damage. Creatures without natural armor, resistance to slashing, or proper leg/footwear take this damage at disadvantage.
Movement through the grass is difficult terrain, unless using trikes or magical elevation (e.g., fly, Misty Step).

Wind Surge (Environmental Event)

Every 3 rounds, a gust of wind whips the grass. All creatures make a DC 15 Constitution save or take 1d4 bleed for the next 3 rounds (nonmagical, cumulative).

Blood Trail

If a creature takes bleed damage, they begin to leave a visible scent trail in the tallgrass. Thri-kreen gain advantage on perception/survival checks to locate them.

🐜 Enemies: Thri-kreen Trappers

Thri-kreen Pack (5 total)

4x Standard Thri-kreen (MM, CR 1) with spined armor and barbed javelins woven from local grass.
1x Thri-kreen Alpha (Custom): Uses hit-and-run tactics, commands insects, and uses thrown chaos-shard bolas that explode in psychic flashes.

📌 Tactics: The Kreen never approach directly. They use the terrain to their advantage—darting in, attacking, and fading into the razorgrass. They strike hardest when the wind surges.

🪓 Optional Twists

A thri-kreen as seen in the fifth edition Dungeons & Dragons Monster Manual. [Image courtesy Wizards of the Coast]

Ole Bessie Returns: The husk of a fallen Demon Grinder lies tangled in vines. It can be reactivated for one dramatic moment of escape—if the party survives long enough to reach it.
Shardstorm Incoming: Mid-fight, a prismatic shardstorm looms on the horizon. If the battle lasts 8 rounds, roll percentile:
- 01–40: Lightning arcs begin to hit randomly.
- 41–80: Shards rain from the sky (Dex save or 3d6 psychic damage).
- 81–100: A portal opens (GM’s choice: escape route or new danger).
The Grass Speaks: A chaos-tainted patch of grass animates and attempts to consume the bleeding. Treat it as a Shambling Mound with slashing aura.

🎯 Victory Conditions

Reaching the ridge and repelling the Thri-kreen without losing more than half the party.
Bonus XP if the party recovers crystal from the grass despite the battle.
Bonus reward: a bladegrass-woven weapon (counts as magical, crits on 19–20, but imposes 1 bleed on user each dawn).

🎭 Narrative Flavor

The Sea of Blades is perfect for tension, attrition, and resource drain. Let wounds feel real. Let blood mark progress. Let them remember the grass. This is not a place to conquer. This is a place to survive.

Thanks for reading. Until Next Time, Stay Nerdy!!