You'll accumulate various resources over time, and knowing how to prioritize them is key. Hero Feathers: Primarily used for promoting heroes to 5-star and merging. Focus on promoting strong 3-4 star units that you use frequently or that have valuable skills for inheritance. Heroic Grails: Used to summon Grand Hero Battle and Tempest Trials+ heroes, and to merge them. Prioritize merging your favorite free-to-play units or those that fill specific niches. Dragonflowers: Used to permanently boost a hero's stats. Use them on your absolute favorite and most frequently used units, especially those with high merge levels, as the stat boosts are more impactful on already strong units.
