Star rating is one of the measures of a hero's power. A hero can be from 1 star to 7 stars, moving up in star rating when promoted with hero shards and Credits. Promoting from 5 to 6 star additionally require an orb, one of which is usually obtained upon completing a raid. Promoting from 6 to 7 stars will require several galactic orbs (dependent on character), which are usually found in raids or solo raid rewards. The seventh star promotion was a new addition in game version 5.0.
Special 3 is unlocked at 3 stars. The level of Passives is capped at the star rating (up to 5; 6 for some). Supermoves are automatically upgraded as a hero move up in star rating (+5%/10%/15%/20%/25%/35% damage for the rest of the match).
For how stats increase and are calculated for both Star rating and Hero Level, see that page.
Unlocking and promoting costs
They are unlocked at 1 or 2 stars. This is a trait inherent to a hero - for example, Green Lantern must be unlocked with 10 shards at 1 star, then promoted with 20 additional shards to 2 star, etc. while Black Canary cannot be unlocked at 1 star and can only be unlocked with 30 shards at 2 stars. This applies to gold and legendary heroes as well.
|Star rating||Required shards||Cumulative total|
They are unlocked at 2, 3, or 4 (Armored Superman only) stars. Most heroes in the game are 2 or 3 star golds; 2 star ones are easier to unlock via shards collected through Campaign, Challenge, etc. but can be harder to promote, because when you obtain a "copy" of them from chests, it is generally 60 shards instead of 160 shards as for 3 star golds.
|Star rating||Required shards||Cumulative total||Credits cost to promote|
|6||300||1100||170K (+ 1 orb)|
|7||360||1460||300K (+5 or 7 galactic orbs)|
|Star rating||Required shards||Cumulative total||Cost to promote|
|6||450||1350||250K (1 orb)|
|7||450||1800||450K(+10 galactic orbs)|
Arkham Knight Batman used to cost 550 shards to upgrade from 4 to 5 stars. Players who upgraded to 6 stars before the update are refunded 100 shards, but it seems those who only got him to 5 stars are not.
It is possible to receive upgrade offers for certain heroes at certain points (unlocking, or reaching a level a multiple of 10). It allows you to directly buy the number of shards required to increase their rating by one star (sometimes along with XP Capsules of the hero's class) with Power Gems. The offer will last an hour.
Offers are time sensitive with two different cooldown periods between offers, depending on the trigger condition. If the trigger condition was a hero unlock, a subsequent unlock promotion offer cannot be triggered for at least 168 hours. If the trigger condition was leveling up the hero past a multiple of 10, a subsequent level up promotion offer cannot be triggered through a hero unlock for at least 120 hours. You can get one offer from each trigger condition back-to-back. After the cooldown period has passed, you can be given the exact same offer again.
If you receive an offer, and then upgrading the star rating with your existing shards, the offer will immediately update to reflect this (e.g. if you get a 3->4 star offer but you upgrade with your own shards, it will turn into a 4->5 star offer). However, you can't get a 6 star offer; if you upgrade to 5 stars on your own, the offer will vanish.
The hero's image used in the offer pop-up seems to be the portrait they have when they are equipped with all 5 pieces of gear even if you haven't collected them all yet.
Interestingly, from the example on the right, despite the second offer stating "saving 66%" instead of 65%, it costs 3 times as much but only offers 2.2 times as many hero shards (without accounting for the XP Capsules). Disregarding the capsules, and prior to the discount, the first offer claims a value of 12.75 Power Gems per gold hero shard, and the second claims a value of 18 gems per shard.
- Increasing a hero's star rating to 6 causes their card's border to gain red highlights.
- Increasing a hero's star rating to 7 causes their card's border to gain glowing neon white highlights
- If you tap on the card of a hero you have not yet unlocked (even if they are 3-star base), you are blocked from seeing their special 3, but its power cost is still shown.