Hero Evolve is the new way to add stats and modifiers to your heroes. They use hero cards and evolve materials to equip and activate/level-up stats and modifiers respectively. The modifiers can become very large, making them extremely useful towards strengthening your heroes.
To get evolve materials, you must participate in Clan Dungeon and win. The higher the level of difficulty you beat, the more rewards you will get. Because it takes several weeks to complete one branch of the evolve tree, this means that to complete them all will be an arduous task if you cannot beat the higher levels of clan dungeon.
This is essentially a perk tree system, except that you can unlock all of them in time. Doing so requires the consumption of evolution materials, of which will take several weeks to build up, and will result in bonus stats and modifiers for your heroes. You must activate the card slots in order, as the ones before the red grade are prerequisites to its activation. When activating different card slots on an evolve tree, it is important to choose a path and complete it all the way to the end before going back and doing the other ones. This is because of the bonus card slots you gain after activating and using one from the perk tree. Once you get all the way to red grade and activate and equip it, you’ll be able to equip seven different hero cards on one hero- something that is much more important than the activation of smaller evolve tree card slots. Please note that the type of cards you will be able to equip will vary depending on which of the hero card slots you have equipped from the evolve tree.
Cards can be found through clan dungeon rewards, with higher difficulties giving both more and a higher grade. They can also be gotten through events. Through the evolve tree you can unlock more card slots and thus equip more cards. Cards give basic number of stats upon equipping and allows you to unlock more though strengthening. Once equipped, you have the option to strengthen them. Cards also come in different types, based on the basic stat that they have. These types will determine if you can equip the cards, depending on which type of card slots you have unlocked (via evolve tree).
Strengthening cards will allow you increase their stars (and will add more to the basic stat), which in turn will activate more of the stats/modifiers they have. The process of strengthening can result in the loss of a lot of coin/evolve points, as the process is entirely RNG based. Evolve points are earned through clan dungeon completion, however they are not used on the evolve tree. They are solely meant for card strengthen and 1000 of them (and 50k coin) are used up on every attempt. Once you run out, you can no longer strengthen. When strengthening you initially start off at a success rate of 100%, and as you gain more stars, the successes rate goes down per each star gained. Beginning with 6*, if you fail a strengthen, your star count will reset to the last multiple of 3 that you achieved. Once you’ve failed once you cannot lose another star until you gain at least one more. E.g. If you are at 11* and a strengthen fails, you will be reset back to 9*. Once you make it to 128 however, then if you fail a strengthen, you will be reset back to 12*. In short, you need to consecutively be successful in strengthening if you want to increase card stars all the way to 15*. Personally, I believe that you should not waste your coin and evolve points on a card that has no % modifiers, but you can of course activate a few of the stars and stats if you want.
Dismantle allows you to take any excess evolution materials or cards that you do not need and turn them into evolve points. Since evolve points are desperately needed to strengthen cards, this is a good way of getting more of them. Keep in mind that it is not a good idea to dismantle evolution materials until all of your evolve trees are fully completed, and it is not a good idea to dismantle cards until all your card slots are filled, as this would be counterproductive towards the overall goal of gaining stats for your heroes.
Grades are present on cards as an indication of how powerful they are in relation to other cards. The higher grade they have, the more stats the card can unlock/the more powerful these stats will be. Cards also have a trophy, which can be viewed in the top left of the card icon. There are bronze, silver, and gold trophies, and the higher the rank of these trophies, the higher/better stats stat will be present on the card.