Hi bro, now I knows that we can get some 侌昜(Ying & Yang) by opening Mythic-Chests every times(Legendary keys or gems).
But unfortunately, one thing is for sure, 3000 Mythical Duplicates and 500000 Gold will definitely not give you a sweet Pleione Lv. 25.
Because we know that upgrading from level 10 to level 11 requires 130 Mythical Duplicates, and upgrading to level 15 to level 16 already requires 425 Mythical Duplicates, and the subsequent upgrade needs will only increase and not less. So even if it's just level 15 to level 25, the consumption is definitely far more than 4250 Mythical Duplicates…
(In addition, the Mythical Card upgrades cost 60 times more gold than the cards)