Duplicates (of Dragons)
From Dragon Mania Legends (DML) Wiki
Duplicates are two or more of the same Dragon species (Dragons with a unique appearance) present at the same time, in a Habitat, on an Island, or in the Dragon Vault. Except for Chronos, Chronoids, and Clan Dragons, Trainers can have duplicates of the same species. In extremely rare cases, usually during large-scale events, duplicate Dragons in the Inventory are considered as such. Most Dragons, acquired through methods apart from buying or breeding, cannot be bought as duplicates until they are obtained, hatched, then placed in a Habitat or the vault.
Dragons that always can be purchased may include:
However, the first three categories of Dragons, and Dragons made available through Breeding Tokens, must first be unlocked as the Trainer progresses through the game. Limited-Time Dragon duplicates whose related event has ended, can only be purchased by tapping their entries in the Dragon Codex tab of the Dragon Codex, they do not appear in the Main Shop.
Dragons purchasable as duplicates are typically buyable in exchange for Gems. Base Dragons are always purchasable using Gold, while Dungeon Dragons are always purchasable using Dungeon Tokens. There is no limit on how many Dragons of the same species can be obtained through breeding, as long as that Dragon is currently breedable. Additionally, Card Dragons (obtained only in exchange for matching Dragon Pieces) can be obtained as duplicates, as there is no limit on the holding amount of their matching Pieces.
The Trainer cannot possess more than one of the same species of Boss Dragon unless that Dragon is made available for purchase in a bundle, promotion, or sale. Since some Dragons must be present on islands to purchase a duplicate, those obtained through a method apart from buying or breeding, will likely never be obtainable again if sold.