You can see a list of default dueling spirits under dueling/spirits/default_spirits.lua. If you want to create your own custom dueling spirits, it is advisable to do this in a new file under the /spirits/ directory.

wOS.ALCS.Dueling:RegisterSpirit({
    Name = "Soul of Lexia Z'oe", -- The name of the dueling spirit
    Description = "Once a noble fighter, the wisdom of Lexia Z'oe lives on and guides you towards greatness", -- The description of the dueling spirit
    RarityName = "Legendary", -- The spirit's rarity name
    RarityColor = Color( 150, 0, 250 ), -- The RGB color of the rarity
    SpiritModel = "models/spirits/lexia_zoe", -- Model path of the spirit
    DuelTitle = "Awakened", -- The title when player enters a duel
    TagLine = "Enlightened by the past", -- The tagline when player enters a duel
    Sequence = "Animation of the dueling spirit",
    ChallengeSound = "sounds/dueling/lexia_zoe_challenge"  
    VictorySound   
    MaxEnergy     
    StartingRoll   
    PassiveLevel   
    Rarity   
    DroppableArtifacts  
             
    
    OnDuelStart    
    OnSpawn    
    OnThink    
    OnDeath    
)