Raise its stars
Why: the most profitable over time — stars are permanent and strengthen the dragon at everything (and grow its army).
What helps directly
Stars (relics)
Stockpile the dragon's relics
Each star demands more and more: gather its relics by opening chests and at the Market.
WhereHatchery chests / Market
Related bonuses (good to know)
Stars (relics)
Recycle the relics of an already maxed dragon
Excess relics from a maxed dragon turn into dust, exchangeable for other relics.
WhereMarket
Keywords
Other needs · Make a dragon stronger