There’s two mechanisms to make a particular hero stronger
- Increase the hero’s level
- For levels 1-9, 10-19, 20-29 etc you are upgrading your hero and you will require crystals of the same element as the hero and coins (details)
- For levels 9-10, 19-20, 29-30 etc you are promoting your hero and you will require hero medals and coins. Promotions unlock bonuses - either for all-heroes (at level 20 and 50) or only for the promoted hero (all other promotions)
- In either case, your hero level is capped by your Player level
- Star up the hero
- Once you get more shards, you can Star Up your hero. You can use gym passes if you have them to cover up a shortfall
- This will immediately boost your Attack and Health stats, but the greater benefit comes when you learn Skills (requires Resource: Rings and coins)
Note:
- There are other ways to get stronger (e.g. Permanent upgrades) but those apply to all your heroes
- Shards can only be used towards that particular hero, so there’s no reason to not star up a hero if you have the shards.
- Gym Passes can be used towards any unlocked heroes, so prioritise their use (my recommendation)
- Hero Medals can be used towards promoting any unlocked heroes, so prioritise their use (my recommendation)