Which research should I prioritize in the late game in Dragonfire?

In the late game, research on the troop type you field becomes the giant multiplier (×11 to ×60). That's where everything is decided — but you have to research the right type.

The common error: maxing the type that's #1 by a hair (e.g. Spearmen 5/5) while your roster mostly fits another type (e.g. Archers, carried by 7+ dragons). You're paying for colossal research that serves only a fraction of your armies.

The right late-game priority:

1. Research for the troop type your entire roster carries best (count how many dragons are green for each type — take the one that lines up the most).
2. "All breeds: Initiative" research (global, helps every army, double effect on turn order and anti-fire).
3. Per-breed Damage for your main hitters.

And since research crushes everything at this stage, one well-researched type means you build all your armies around it — consistent with the "1 army = 1 troop type" rule. Choose your axis by looking at your roster, not at the raw ranking of your research.