This creature cant be blocked by creatures the monarch controls
They work against mill in a similar fashion: Shuffling your library back into your deck against a mill deck is equivalent to resetting your life total to 20, 40, or whatever against a more standard Magic deck attacking your life total
However, destruction isnt the only way to get rid of a monster
This archetype is used by Professor Cobra (Professor Thelonious Viper) in GX
To be able to cast Ureni, Id need to go to 4 Fabled Passage, but doing that along with the Conduit Pylons I am already running opens up Molt Tender to address the out of the gates a bit slow problem
Overall, the gacha system in Pokemon TCG Pocket leans toward Regular packs with low probabilities for rare cards, creating a challenging experience for completing a deck.