These cards will likely release in English in the second Mega series expansion, and we theorize itll be that sets equivalent of Hyper Rare.
As a player, shaping that narrative is in your hands
There will often be cards from that set included in the Masterpiece Series (like how the Battle for Zendikar rare dual lands were included in Zendikar Expeditions ), but they will typically exist in the set in a traditional frame in their normal rarity in addition to appearing in the Masterpiece Series
It's far more important to mulligan if you don't have a good land base in your opening hand, but a Control deck can seriously suffer from a smaller starting card pool - so mulligan wisely
Mistblade Shinobi Mistblade Shinobi is a ninja that can return your creatures for value or bounce your opponents creatures to help tempo them out and trigger more ninjutsu activations
The Showcase frame will absolutely add to this cards ongoing popularity, with the V.A.T.S-inspired style increasing the value of almost any card that can include it