Impervious Greatwurm Impervious Greatwurm is a massive 16/16 wurm with convoke, so its an easy cast at an otherwise large 10-mana
Forced Discard The strength of Black is the ability to disrupt your opponent in ways other colors can rarely achieve, with the ability to force your opponent to discard cards in their hand
Although green doesn't have great ways to deal with creatures and no way to effect peoples libraries, hands or the spells they cast and therefore qualifies as light on disruption green can deal with all other non-creature permanent types quite efficiently
For three mana, Azcanta, the Sunken Ruin lets you look at the top four cards of your library and put a nonland card among them into your hand
It looks like Historic on MTG Arena influenced these card choices, which likely led to Walking Ballista and some other cards not showing up
Slowly but surely, he schemes his way into power