how do battle siege cards work mtg Top 10 in Magic: The Gathering March of the Machine Mechanics

Company: Wizards of the Coast Brand: Magic The Gathering Series: Amonkhet Item Type: Booster Pack Release Date: April 28th 2017 UPC: 5010993330492 Stock #: 537614 Our Guarantees to You, Our Valued Customer

Like other permanent spells, you can only cast it during your main phase when the stack is empty, i.e., when you could normally cast a sorcery

In this case, because your life total also can't change, that damage has any other effects that it may have aside from causing you to lose that much life (such as effects from lifelink or infect) and triggers and effects can see that damage was dealt even though your life total didn't change

On this card, we see a depiction of Avenger's Tower