The Clashing Gates
A boarding battle between rocks that hate ships.
📜 Session Summary
| Style Kinetic trireme gauntlet for 6 level-8 PCs, mixing helm checks, boarding fights, and hard navigation choices. |
| Win Condition Thread the Symplegades with the ship intact enough to sail and the Titan-kin boarding rite broken. |
| Loss Condition The rocks learn the ship's name, crush the route shut, and leave survivors stranded on living stone. |
| Players 6 × Level 8 · 3–3.5 hrs · 3 encounters |
| Key Ally Kyane the Blue Oar (recruit Enc. 1) · Maguffin: Bronze Dove of Phineus |
Description
Captain Philon of the Mist Trireme hooks the party. Maguffin Bronze Dove of Phineus pays off in the finale against Brontes Gate-Heir. Recruit Kyane the Blue Oar along the way.
Time a trireme run through the Symplegades as Titan-kin board from both rocks.
Major Beats
- Philon's confidence cracks when the rocks answer the trireme's old name.
- The first omen is useful but not complete.
- Boarders attack the ship's timing more than its crew.
- The finale rewards choosing exactly when to fight and when to row.
Creature / Enemy List
| Creature | Easy | Med | Hard | Notes |
|---|---|---|---|---|
| Rock-Grappler Raider | — | med | hard | CR 3 · Boarding skirmisher |
| Tide-Ogre Bosun | — | med | hard | CR 5 · Deck breaker |
| Stone Scion of the Gates | — | med | hard | CR 6 · Titan-kin controller |
| Brontes Gate-Heir | — | med | hard | CR 10 · Boss boarder |
| Kyane the Blue Oar | — | 1 | 1 | Recruit Enc. 1 |
Encounter 1 — Dove Before Oars
Overview
Approach the breathing rocks, test the current, and decide whether to trust omen, crew, or speed.
🗺 Terrain
Trireme deck, fog lane, left and right rock faces, current arrows, and three ship zones.
Mechanics
- Navigation challenge: 5 successes before 3 failures at DC 15 using vehicles, Athletics, Perception, or Survival.
- The Bronze Dove grants advantage and tells which rock will move first.
- Recruit Kyane by honoring her cadence; she grants one ship-check reroll per later encounter.
- Failure damages a ship zone or starts Encounter 2 with Rock-Grapplers already aboard.
Creature Cards
Captain Philon of the Mist Trireme
Veteran navigator, quest giver
Motivation. He must prove a safe western route before the fleet commits to the passage.
Secret. He once lost a crew here and still hears their oars in the fog.
Hard rule. He will sacrifice cargo before crew, but not the ship's dove unless convinced it saves everyone.
Bronze Dove of Phineus
Clockwork omen, passage key
Appearance: Palm-sized bronze dove with one real white feather in its throat.
Handout. "If it returns with clipped wings, row. If it returns whole, pray faster."
Enc. 1–2. Launch it to scout currents, granting advantage on one vehicle (water) or Perception check.
Enc. 3. Its wingbeat names the safe count; spend it to cancel one rock-clash or expose the Titan-kin anchor.
Kyane the Blue Oar
Medium Humanoid, Neutral · Recruitable Ally · Champion rower and boarding repeller
AC 16 | HP 83 | Speed 30 ft.
Role: Champion rower and boarding repeller
RECRUITMENT (Enc. 1). Let her call cadence during the first crush, or beat her honest in a rowing contest.
Aid. Acts on party initiative when recruited; prefers nonlethal when asked.
Strike. Oar-staff +7 to hit, 14 bludgeoning; grants one reroll on a failed ship check.
Rock-Grappler Raider
Medium Creature · CR 3 · Boarding skirmisher
AC 16 | HP 74 | Speed 30 ft.
Note. Falls inert if shoved into open water between clashes.
Attack. Stone hook +6 to hit, 13 piercing and pulls target 10 ft toward a rail.
Encounter 2 — Boarders From Both Stones
Overview
Titan-kin leap from both cliffs to pin the trireme in place while the gates start closing.
🗺 Terrain
Main deck with mast, two boarding bridges, stern helm, damaged oar banks, and rail hazards.
Mechanics
- At initiative 20, choose: rocks close 20 ft, a ship zone takes damage, or two raiders board.
- Non-combat option: beat the Tide-Ogre's cadence with Performance/Athletics DC 16 to stall one bridge.
- Repairing an oar bank takes an action and tools or Strength DC 15; Kyane makes it a bonus action once.
- The Bronze Dove can identify the Stone Scion sustaining the anchor chant.
Creature Cards
Rock-Grappler Raider
Medium Creature · CR 3 · Boarding skirmisher
AC 16 | HP 74 | Speed 30 ft.
Note. Falls inert if shoved into open water between clashes.
Attack. Stone hook +6 to hit, 13 piercing and pulls target 10 ft toward a rail.
Tide-Ogre Bosun
Medium Creature · CR 5 · Deck breaker
AC 15 | HP 118 | Speed 30 ft.
Note. Can be distracted by a shouted cadence contest.
Attack. Anchor maul +8 to hit, 20 bludgeoning and damages a ship zone.
Stone Scion of the Gates
Medium Creature · CR 6 · Titan-kin controller
AC 17 | HP 132 | Speed 30 ft.
Note. Maintains the anchor chant that teaches the rocks the ship's name.
Attack. Shard hymn DC 16 Con, 24 thunder and speed halved.
Kyane the Blue Oar
Medium Humanoid, Neutral · Recruitable Ally · Champion rower and boarding repeller
AC 16 | HP 83 | Speed 30 ft.
Role: Champion rower and boarding repeller
RECRUITMENT (Enc. 1). Let her call cadence during the first crush, or beat her honest in a rowing contest.
Aid. Acts on party initiative when recruited; prefers nonlethal when asked.
Strike. Oar-staff +7 to hit, 14 bludgeoning; grants one reroll on a failed ship check.
Encounter 3 — The Count Between Clashes
Overview
Run the final gap while Brontes lands on deck and the stones try to remember the ship forever.
🗺 Terrain
Narrowing channel, sliding deck markers, exposed ram, anchor-chain to right rock, and stern escape wake.
Mechanics
- Seven-count clock: each round PCs assign helm, oars, repairs, and boarder control before the rocks move.
- Spend the Bronze Dove to cancel one rock-clash or reveal the anchor-chain's weak link.
- Win by cutting the anchor-chain and clearing the gap, forcing Brontes overboard, or bargaining with his honor.
- If the ship reaches 3 broken zones, it still escapes only if PCs jettison cargo or beach on a living rock.
Creature Cards
Brontes Gate-Heir
Large Creature · CR 10 · Boss boarder · Boss
AC 18 | HP 210 | Speed 40 ft.
Role: Boss boarder
Note. Victory can be cutting his anchor-chain and outrunning him through the clash.
Hard encounter focus. Win condition may be steal, escape, disable, or drive-off — not always kill.
Multiattack / Assault. Titan hammer +9 to hit, 24 bludgeoning plus 10 thunder to the deck.
Advance (1). Move up to half Speed.
Strike (1). One attack from Assault.
Bronze Dove of Phineus
Clockwork omen, passage key
Appearance: Palm-sized bronze dove with one real white feather in its throat.
Handout. "If it returns with clipped wings, row. If it returns whole, pray faster."
Enc. 1–2. Launch it to scout currents, granting advantage on one vehicle (water) or Perception check.
Enc. 3. Its wingbeat names the safe count; spend it to cancel one rock-clash or expose the Titan-kin anchor.
Kyane the Blue Oar
Medium Humanoid, Neutral · Recruitable Ally · Champion rower and boarding repeller
AC 16 | HP 83 | Speed 30 ft.
Role: Champion rower and boarding repeller
RECRUITMENT (Enc. 1). Let her call cadence during the first crush, or beat her honest in a rowing contest.
Aid. Acts on party initiative when recruited; prefers nonlethal when asked.
Strike. Oar-staff +7 to hit, 14 bludgeoning; grants one reroll on a failed ship check.
Stone Scion of the Gates
Medium Creature · CR 6 · Titan-kin controller
AC 17 | HP 132 | Speed 30 ft.
Note. Maintains the anchor chant that teaches the rocks the ship's name.
Attack. Shard hymn DC 16 Con, 24 thunder and speed halved.
⚖️ Difficulty Scaling
As Written ★ — 6 Players, Average Level 8
- Baseline for this guide. Numbers, DCs, and win tracks assume six PCs at average level 8.
Library Standard — 6 Players, Average Level 8
- Identical to As Written — this guide’s baseline is already 6 PCs at average level 8.
Easier
- APL 4–6: reduce minion counts ~30%; DCs −2; boss loses one recharge or legendary option.
Harder
- APL 10–12: boss HP +25–35%; +1 legendary action; add a lieutenant or extra wave.
📋 Appendix — Cards
Captain Philon of the Mist Trireme
Veteran navigator, quest giver
Motivation. He must prove a safe western route before the fleet commits to the passage.
Secret. He once lost a crew here and still hears their oars in the fog.
Hard rule. He will sacrifice cargo before crew, but not the ship's dove unless convinced it saves everyone.
Bronze Dove of Phineus
Clockwork omen, passage key
Appearance: Palm-sized bronze dove with one real white feather in its throat.
Handout. "If it returns with clipped wings, row. If it returns whole, pray faster."
Enc. 1–2. Launch it to scout currents, granting advantage on one vehicle (water) or Perception check.
Enc. 3. Its wingbeat names the safe count; spend it to cancel one rock-clash or expose the Titan-kin anchor.
Kyane the Blue Oar
Medium Humanoid, Neutral · Recruitable Ally · Champion rower and boarding repeller
AC 16 | HP 83 | Speed 30 ft.
Role: Champion rower and boarding repeller
RECRUITMENT (Enc. 1). Let her call cadence during the first crush, or beat her honest in a rowing contest.
Aid. Acts on party initiative when recruited; prefers nonlethal when asked.
Strike. Oar-staff +7 to hit, 14 bludgeoning; grants one reroll on a failed ship check.
Rock-Grappler Raider
Medium Creature · CR 3 · Boarding skirmisher
AC 16 | HP 74 | Speed 30 ft.
Note. Falls inert if shoved into open water between clashes.
Attack. Stone hook +6 to hit, 13 piercing and pulls target 10 ft toward a rail.
Tide-Ogre Bosun
Medium Creature · CR 5 · Deck breaker
AC 15 | HP 118 | Speed 30 ft.
Note. Can be distracted by a shouted cadence contest.
Attack. Anchor maul +8 to hit, 20 bludgeoning and damages a ship zone.
Stone Scion of the Gates
Medium Creature · CR 6 · Titan-kin controller
AC 17 | HP 132 | Speed 30 ft.
Note. Maintains the anchor chant that teaches the rocks the ship's name.
Attack. Shard hymn DC 16 Con, 24 thunder and speed halved.
Brontes Gate-Heir
Large Creature · CR 10 · Boss boarder · Boss
AC 18 | HP 210 | Speed 40 ft.
Role: Boss boarder
Note. Victory can be cutting his anchor-chain and outrunning him through the clash.
Hard encounter focus. Win condition may be steal, escape, disable, or drive-off — not always kill.
Multiattack / Assault. Titan hammer +9 to hit, 24 bludgeoning plus 10 thunder to the deck.
Advance (1). Move up to half Speed.
Strike (1). One attack from Assault.