Attributes of heroes
Each hero has several attributes, which can be changed -discover it in the following article.
Hero levels
Each character has a certain quantity of levels to achieve. Leveling up allows them access to new abilities and positively affects the hero's health, which increases by a small amount at each level-up.

The number of accessible levels depends on the rarity and evolution of the hero. The following are the level caps that relevant for each degree of rarity:

Ordinary — 40/50* levels
Unusual — 50/60* levels
Rare — 60/70*/80* levels
Epic — 80/90*/100* levels
Legendary — 90/100*/110* levels
Mythical — 100/110* levels

*represents the maximum level of evolved cards.
Experience
Experience (game mechanic that allows characters to level up after reaching certain amount of experience) isn't gained over time, it has to be earned through different ways.

Here they are:

1. Send your squad to PvE campaigns/engage in battles conducted on the PvP arena.
2. Consume an item called "Experience's elixir" (which you can purchase or obtain during a fight).

We will dedicate a special article to leveling up.
Evolution
Experience (game mechanic that allows characters to level up after reaching certain amount of experience) isn't gained over time, it has to be earned through different ways.

Here they are:

1. Send your squad to PvE campaigns/engage in battles conducted on the PvP arena.
2. Consume an item called "Experience's elixir" (which you can purchase or obtain during a fight).

We will dedicate a special article to leveling up.
Abilities
Each hero has its own active ability, which is enabled after several turns (moves).

Below are some of the abilities:

The Ancestor's Protection — your character goes into a defensive formation and takes reduced damage (by 40%) for 2 turns;

Shoulder to Shoulder — while attacking, your hero increases its harm for additional 50% of the total damage of his race. This ability deals damage to all enemy targets (i.e. it's ultimately scalable);

Witch Doctor — fills his allies with hope and instantly restores 10% of health to all friendly heroes;

Shield — character's lust for battle becomes so strong that he's unable to die for 1 turn (no matter how wounded he becomes);

Bloodsucker — attacks for 100% of the total race's damage and steals health from the adversary (by doing so, your character heals in accordance with the damage done);

Vengeance — hero returns 50% of damage done to him back to enemy that launched an attack;

Curse — leaves a trail of poison that deals damage to enemies caught in the path for 2 turns (equivalent to 150% of the race's damage);

Dodge — character's combat prowess allows him to dodge 30% of incoming attacks;

Headache — stuns all enemy warriors for 1 turn;

Unity — your card deals 200% of the total race's damage against 1 target;

Substitution — changes all the heart stones for stones of the race.
How to increase the card's rarity?
Unnecessary cards are converted into essence, using which you can create a cards one level of rarity higher.

While transforming a certain number of ordinary cards (and therefore obtaining the required amount of essence) you can create 1 unusual card.

Pretty soon will devote a special article to explain you how it works.