Upon clicking any of the cards within your collection, you may notice a column defining a card's BCX, or "base card experience," located next to any card's "Lvl" (level). BCX represents the total number of this copy of a card combined into one card, which eventually affects a card's level once enough copies are combined.
Upon clicking on the "Stats" tab within the same page displaying the BCX of the card, you will see a list of levels this card can achieve. To the right of the levels, you will see a column that displays the number of cards needed to be combined to achieve the listed level for the card (circled in green). If you want to level this card up to level 4, then 25 copies are needed. If you want to level this card up to level 5, 40 copies are required instead.
Four columns display the colors grey, blue, purple, and gold to the right of the "LVL" and "CARDS" columns. In order, these colors represent "common," "Rare," "Epic," and "Legendary." For a summoner (like the image above), this allows you to determine what levels your monsters will be capped. Summoners' level caps are linked to a league.
The league caps can be found on the battle screen. Click on the "Leagues" button to proceed.
Next, click on the appropriate league within the new window to see the summoner limits based on the particular league.
As you can see here for an example, the league limits in the silver league for summoners are as follows:
- Commons: Level 5
- Rares: Level 4
- Epics: Level 3
- Legendaries: Level 2
When entering a monster's stat page, you will see columns representing various attributes and abilities, with slight differences per level. Sometimes a card may lose an attribute point during a level-up, but the monster will get a useful ability in exchange. An example of this can be seen in the card "Demented Shark," losing one point of max health in exchange for gaining the ability "Thorns" when advancing from level 5 to level 6.
Sometimes they may even lose a lesser attribute in exchange for buffing a more powerful attribute, such as when the Demented Shark reached a total of 220 cards combined (level 8). At this level, it loses the point of health again after gaining it back at the previous level but gaining an extra point of melee attack power.
You will see the rarity bubble for each card (circled in red above). The grey bubble on the Demented Shark represents the common rarity. The purple bubble on Lobstradamus represents the epic rarity. So in the silver league, if you utilize a level 4 rare Kelya Frendul summoner as displayed before, you can use the Demented Shark up to a maximum of level 5. Lobstradamus can be used up to a maximum of level 3. If you only possess a level 1 Kelya, all monsters will have stats downgraded to level 1.
When this happens, you will see a message: "This Monsters's level is limited by the level of the currently selected Summoner. Level up your summoner to use higher level of this monsters". The yellow triangle can recognize this situation with the exclamation mark.