After poring over the lists again and again, there are cards that are open-ended, but none of the decks have a cluster or package that is clearly designed to be a seed for a different commander deck entirely
Hopefully there will be an update for this
With this ability, the player either gains a three-card advantage, or drags their opponent toward slowly (but surely) milling their decks, which leads to an instant loss if the opponent has no more cards to draw at the beginning of their turn
Currently, all Sieges in the game come from the same set, March of the Machine, and this is the only type of Battle card released thus far
Once you cast it, its an instant spell for as long as it exists on the stack
Minor card changes may occur if items are out of stock