Ruins of Atlantis
- Location: Atlantic Ocean Floor
- Depth: 3339 Meters (10991 FT)
- Power Source: Atlantean Font of Power
- Age: Several Thousand Years
Millennia ago, a race of ancient and mysterious beings built a great city on an island in the South Atlantic. After a series of wars rocked their civilization, the island was abandoned and eventually sank beneath the waves.
Now, thousands of years later, its ruins have been discovered on the ocean floor, and the rush is on to possess the secrets of Atlantis! This ancient city will once again be a battleground, as heroes strive to keep powerful, archaic weapons out of the hands of the most nefarious villains in the Multiverse!
- References for Cards in this deck and in other decks. See the full list here.
- Link to sources for confirm-able information, separate unconfirmed in a different section, RL Card References in a third, and Art References in a fourth. See This page for more detailed information on how to categorize references
- Baron Blade launched his Terralunar Implusion Beam Doomsday Device from this location Baron Blade Letters Page Episode
- Kismet escapes The Block through a Portal and ends up here. This is the place where Kismet's main confrontation with the heroes occur as weird events start happening around the world as she gathers power from the artifacts here. Kismet Letters Page Episode
- Atlantis is a location in both the DC and Marvel universe. In DC, it is the home of Aquaman. In Marvel, it is home to Prince Namor. Fittingly, the ocean-based hero of the Sentinels universe, Tempest, is tied to the city's history.
- Atlantean Font of Power (x1)
- At the end of the Environment turn, play the top card of the Villain deck. Play the top card of each Hero deck in turn order. If the played card is a Limited card already in play, discard that card and play the next card. At the start of the Environment turn, destroy this card.
- Art: The Atlantean Font of Power;
- Flavor text: In the middle of the expansive chamber stood a fountain, not flowing with water, but with some thick glowing liquid…
- Hallway Collapse (x2)
- When this card enters play, deal each Target 3 Melee Damage. At the end of the Environment turn, destroy this card.
- Art: Legacy struggling to keep a hallway from collapsing on him;
- Flavor text: With barely any warning, the low rumbling in the ceiling of the stone hallway turned to a roar as rocks began to fall around the heroes!
- Leaking Room (x2)
- Players cannot play Hero cards. Increase all Lightning Damage by 2. At the start of the Environment turn, destroy this card.
- Art: The Visionary looking at water seeping in from a crack in the glass;
- Flavor text: "Quick! Get to the exit!" yelled Tempest, arms outstretched against the fast approaching wall of water.
- Mystical Defenses  (x2)
- At the end of the Environment turn, this card deals each non-Environment Target 2 Energy Damage.
- Art: An energy beam shooting out from the Mystical Defenses on a pillar;
- Flavor text: Violet and emerald beams of energy blazed from concealed points in the elaborately carved walls, striking down everything they touched!
- Phosphorescent Chamber (x2)
- Increase all damage dealt by 1. Increase all HP recovery by 1. At the end of the Environment turn, each Player must discard a card. At the start of the Environment turn, each Player may discard 1 card to destroy this card.
- Art: Tempest holding up a light in a room to see markings on the ceiling;
- Flavor text: Upon entering the glowing chamber the heroes could feel the arcane energies coursing through their bodies…
- The Pillars of Hercules (x1)
- Players may play an additional card, use an additional power, and draw an additional card on their turns. At the start of every turn, play the top card of the Villain deck. At the start of their turn, a player may skip the rest of their turn to destroy this card.
- Art: A silhouette of Legacy, Absolute Zero, Bunker, the Wraith, and Baron Blade standing before the Pillars of Hercules;
- Flavor text: Radiating an eerie light, the giant crystalline pillars had stood beneath the ocean for centuries.
- Toxic Seaweed (x2)
- Whenever a Hero uses a Power, deal that Hero minus 1 Toxic Damage. At the end of the Environment turn, 1 Player may discard their hand to destroy this card.
- Art: Closeup of the Toxic Seaweed;
- Flavor text: The damp green leaves that clung to the ancient walls reeked of rotting flesh and bile, repulsing those who entered the room.
- The Kraken  (x3)
- At the end of the Environment turn, this card deals the non-Environment Target with the lowest HP 5 Melee Damage.
- Art: A tentacle breaking through a wall to grab Vyktor;
- Flavor text: The mighty tentacle burst through the stone wall, knocking Tamar against a pillar as water began pouring in to fill the room.
- Pillars of Hercules
- This card reads "Players may play an additional Card, use an additional Power, and Draw an additional Card on their turns. At the start of every turn, play the top Card of the Villain Deck. At the start of their turn, a player may skip the rest of their turn to destroy this card." Because the two effects are printed on separate lines on the card, the two effects occur sequentially and not simultaneously. That means that the first line ("play the top Card of the Villain Deck") will happen before the first player has a chance to skip their turn to destroy the card.
- Atlantean Font of Power
- This card reads "At the end of the Environment turn, play the top Card of the Villain Deck. Play the top Card of each of the Hero Decks in turn order. If the played Card is a Limited Card already in play, discard that Card and play the next Card". The intent of the card is to have players keep attempting to play cards until a valid play occurs, so if the next card you play is also a limited card that's already in play, you'll keep going, repeating as necessary until you uncover a card that isn't limited and already in play.