For a duel to happen, a clan must first build a Duel Room. Once complete, a player enters the arena and walks up to one of the white sets of rings and activates. The player will sit down and wait for another challenger while Lotus announces to other Tenno in the Dojo that a challenger is present. Another Player may enter and activate the other set of white rings. In a moment the players will be told the round is starting. They will have 3 seconds to move about the arena. They may fire their weapons but no damage will be applied until the 3 seconds are up. Once the timer is up, a 60-second timer will start.
The players will start with full health, shields, and 50 energy. Two energy orbs are available either side of the arena above a set of blue rings. These orbs grant 50 energy. They spawn as the 3 second timer ends and respawn every 10 seconds from being picked up.
A round is won once a player is brought to 0 health. The first player with 2 wins takes the duel. Upon death, the round will restart with both players being brought back to full health and shields will recharge. A 3-second timer will start to count down and the 60 second timer will restart.
The Arena is locked. Other players may watch the game from outside. They are allowed to run about and see it from any angle, but they are not allowed to enter the arena once the fight has begun.
- A spectator kneeling at the side of the arena can be knocked backward and get stuck inside the wall upon a duelist using a heavy melee jump attack with large AoE such as Reaper Prime or Fragor.
- Using Ash's Blade Storm will instantly kill everyone in the Dojo. You have to leave the Dojo to be alive again.
- Sometimes after a match, the two players that were fighting would be teleported out of the arena and still have their weapons. They would be able to fire and kill anyone in the Dojo at the time, after you run out of ammo, your gun will go on your back as normal. You also can't enter the arena while holding your gun out.
- Due to lag, a player not participating in the duel will be teleported on the borders of the arena or in the arena. The player cannot be killed (their shields will take damage but not their health), but sentinels will target them and status effects will still apply (except for bleed, toxin, and viral because the player's health cannot be damaged). After the duel is over, the player may exit the arena. Note: the player cannot attack with their weapons or powers (Not confirmed if sentinels will attack) but can dive-kick the players dueling. This will cause a knockdown and help the other duelist.
- While a duel is underway, clan members are able to access the decorations menu and place objects on the invisible wall which forms to prevent observers from entering the arena. This glitch can allow for the creation of flying props.
- Using Excalibur's Radial Blind just as you get killed will blind the opponent permanently, or until the ability is used again.
- (Spoilers) If Excalibur Umbra is equipped, entering operator mode will cause Excalibur umbra to attack his operator until he is killed, in which case he will stop moving until exiting operator mode. Excalibur Umbra has a limited range, and will not attack the operator if they are on opposite sides of the room.