Every world in every universe is a simulation created by an interdimensional network of servers. These worlds are maintained by the goddess Exiva and the Motes, sentient computers that serve her. To keep the worlds safe from harm, the Motes choose heroes from across the worlds and unlock their inner power, transforming them into one of their champions known as the Blade Strangers.
When a being named Lina appears and begins consuming the servers' data, countless worlds are lost, with all the Blade Strangers falling before her. To protect the universe, the Motes transmit several heroes from the remaining worlds to their plane and alter their memories to make them believe they are participating in a fighting tournament, believing the last hero standing will be awakened as the new Blade Stranger and defeat Lina once and for all.
Gameplay in Blade Strangers takes place on a 2D plane and uses four attack buttons. The game avoids the use of more complex input motions seen in other fighting games such as quarter-circles and dragon punches; instead, players use a single directional input combined with a button to perform their moves, similar to the Super Smash Bros. series. During battle, players can build meter by dealing and receiving damage, which can be spent to unleash EX Special Attacks and powerful super moves against their opponent. Once per round, when a character is running low on health and has a full meter remaining, players can enter a temporary “Heat Up!” state, granting them increased attack speed and full armor for its duration.
The game offers a single-player story mode, with characters interacting with one another while progressing through a tournament ladder, along with arcade, survival, challenge and training modes. The game also supports local and online multiplayer battles.
Blade Strangers features twelve playable characters drawn from different independent game franchises, primarily other Studio Sanzensen and Nicalis works, along with two original characters for a total roster of fourteen. Each character also receives a stage based on their game of origin.