Which dragons should you build as a free-to-play player?

As a free-to-play player your relics and Cores are scarce: you have to choose and stop spreading yourself thin. The priority logic:

1. One dragon per army type you actually play (a lead with the right affinity: spearmen, archers, cavalry…).
2. Star Rank first on those leads — it's permanent, it unlocks Habit slots, and some effects only switch on at 6★ or 10★.
3. Then the set Habit ⭐ (the one that reinforces the Order), raised with a Breedmark + Core.

Don't get hypnotised by raw Power 🔥: a well-starred dragon with live Habits beats a "big number" dragon standing there naked. Aim for 2-3 pivot dragons at most and take them far, rather than 10 dragons half-built.