Disciplined Duelist

Double strike
This creature enters with a shield counter on it. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)

Brokers agents defend their charges by all means available, from intricate logic to blunt force trauma.

Streets of New Capenna

Double strike
Disciplined Duelist enters the battlefield with a shield counter on it. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)

Double strike
Disciplined Duelist enters the battlefield with a shield counter on it.

"Shield" is not an ability that creatures have and shield counters are not keyword counters. If a creature with a shield counter loses its abilities, the shield counter will still protect it as normal.

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.

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.

If a permanent with a shield counter is dealt unpreventable damage, that damage will be dealt and a shield counter will still be removed.

Removing a shield counter in this way isn't the same as regenerating a creature.

Shield counters don't prevent players from sacrificing creatures.