Diamond City

2024-03-08 A creature with a shield counter on it may still be destroyed by state-based actions if it has damage marked on it equal to its toughness or has been dealt unpreventable damage by a source with deathtouch.
2024-03-08 If a permanent that would be dealt damage has more than one shield counter on it, that damage is prevented and only one shield counter is removed.
2024-03-08 If a permanent with a shield counter is dealt unpreventable damage, that damage will be dealt and a shield counter will still be removed.
2024-03-08 Removing a shield counter when a permanent would be dealt damage or destroyed isn't the same as regenerating a permanent.
2024-03-08 Shield counters don't prevent players from sacrificing permanents.
2024-03-08 "Shield" is not an ability that permanents have and shield counters are not keyword counters. If a permanent with a shield counter loses its abilities, the shield counter will still protect it as normal.

Card is in preconstructed decks:

mtg.wtf