When Angel of Serenity enters the battlefield, you may exile up to three other target creatures from the battlefield and/or creature cards from graveyards.
When Angel of Serenity leaves the battlefield, return the exiled cards to their owners' hands...
Whenever Archon of the Triumvirate attacks, detain up to two target nonland permanents your opponents control. (Until your next turn, those permanents can't attack or block and their activated abilities can't be activated.)..