Players are presented with 3 random monsters out of a pool and must select one to be on their team. The process is repeated until the player has a full team of 3 monsters. The monsters come with default preset skills and runes, however the skills and runes may be swapped after the monster is selected. Players do not use their own runes and instead may select any level 6 runes they like. Monsters are set at level 100, although they may have accessed to ranked skills.
Players compete in up to 6 matches, with each win earning them more and better rewards. After 2 losses, players cannot keep fighting and must collect their rewards.
Live Duels also make use of skill warm ups, as shown by tapping the "Tournament" button when viewing a monster's skills. Skills that must warm up include: all area control skills (freeze, stun, cooldowns activated, 100% stamina removal, possession, corrupted, total blind, and all skills that grant an extra turn) and all single target mega control skills (mega stun, mega freeze, mega possess, and mega corrupted).
In Classic Duels, players can enter by spending 4 Duel Tickets (earned from completing Daily Goals) or 5 gems.
To enter in Grand Duels, players must spend 6 Grand Duel Tickets (only earned as Grand Duels prizes) or 30 gems.
Grandmaster Duels are recurring duels that are only available for a limited time and coincide with a special Timed Challenge. Players choose their monsters from a predefined list of their own monsters and their own runes. Monsters are capped at level 115, runes are capped at level 7, and relics are not used. Entering in Grandmaster Duels costs 30 gems.