The Shroud role is a neutral role where the Shroud selects someone via their kill button and they must kill before the next meeting is called, or the selected player dies themself. Here is my idea: The Shroud can only pick one player to shroud. Additionally, the Shroud must kill before the next meeting is called to keep their shrouded player under control. If the Shroud fails to do so, they can select another player to "shroud".
Think like the Crown of Madness spell in Dungeons & Dragons (2nd-level enchantment). Once the spellcaster breaks concentration on the spell, they can cast it again.