The Legendary Mystic Summon is a rotating feature that will sometimes appear on selected Summon Gates as a free extra.
If a player does not have sufficient Coins/Tokens to make a single summon in a Summon Gate where the Legendary Mystic Summon is available, the “Summon” button will transform to indicate a free summon is available.
Tapping the button offers a choice to watch an ad or dismiss the Legendary Mystic Summon. If the free summon is dismissed, it will not appear again for the remainder of that Summon Gate’s duration.
There is a limit of one Legendary Mystic Summon per Summon Gate occurrence. If the Legendary Mystic Summon appears on a future occurrence of the same Summon Gate, it can be drawn again. The Legendary Mystic Summon shares the same pool of Heroes as the Summon Gate on which it appears, but the Hero appearance rates are different.