Since the 10th of August, Kashtira has been added to Master Duel. Due to lacking its strongest asset in Arise-Heart, and additional great cards in Kasthiratheosis and Big Bang, a 'pure' version might not reach tiered status but Fenrir will be stacked on some decks and is definitely a strong addition to the game.
Below you'll see the decklist used in my video, with in the side-deck some other options you can consider running.
Do keep in mind, this is far from a streamlined version of the deck, and it focusses heavily on the banishing and zone locking part, which may not necessarilybe the best strategy at the moment.
Good luck!
P.s. Still need to figure out some proper Small World lines, but it is definitely worth considering to up the consistency.