L5Rs feudal Japan-inspired world has been expanded further in a tabletop RPG and board game Battle for Rokugan, so theres plenty more to dive into once you find yourself hooked
however, there really arent great counters cards to go along with them, and the nature of mutate as a mechanic doesnt really lend itself to the geometrically scaling bonuses of some counters-based strategies
Plus, when you dont need to trade them in to destroy those lands, you can tap them for colorless mana to activate Eldrazi Displacer
Untaidake has a tempo loss, produces only colorless mana, loses you life, and its mana can only be used for legendary creatures
For example, one of the best additions to your deck would be Vizier of the Scorpion , which gives all your Amass tokens Deathtouch