Sylvion: Below Ground

About this expansion

Sylvion: Below Ground is a 16-card expansion for 1–2 players that adds an additional challenge to Sylvion, with a listed play time of 15 minutes.

To set up, shuffle the expansion cards and place them face down in the battlefield’s 4×4 grid. These hidden terrain cards remain concealed until you try to place a tree or fountain on a terrain card.

Whenever you want to build, you must first pay the cost and then reveal the terrain card. What you discover determines whether your planned placement succeeds cleanly or triggers another effect.

• Unoccupied terrain: Remove the revealed card from play and place the tree or fountain in that space.
• Owl: Remove the card, place the tree or fountain in the space, then draw two cards from the defender deck.
• Swallower: Remove the card along with the tree or fountain you intended to place. You receive no compensation.

Fountains have one additional rule when a swallower appears. After the fountain is removed, draw one card from the defender deck as if the fountain had been defeated in battle.

This compact expansion turns each attempted construction into a reveal with possible consequences. The face-down grid keeps the contents unknown until you commit resources, while owls and swallowers create distinct outcomes for the same basic building action.

With its small card set and direct integration into the battlefield, Sylvion: Below Ground offers a focused extra challenge without changing the core placement procedure: pay first, reveal the terrain, and resolve what lies beneath.