Listen here , babystopped reading there <| sep |> they all going to china to get enslaved . <| sep |> Here is Leeloo Dallas Multicat . 3 ! <| sep |> The character would always think they are hidden until a monster shows them otherwise and some might pretend and not show him they know where he is . Yes he can be hidden from some and not others . It depends on what happens next . If he attacks his cover ' ll be blown . If one of the monsters gives him away Klurg ! Burgtok ! De elfs is over dere ! etc then he might not be hidden from them anymore . The benefit is he gets advantage yada yada against foes he is hidden against . So if he isn ' t hidden anymore , not advantage . He won ' t know he doesn ' t have it until something tells him he doesn ' t . Orc sees him . Ready an Action to attack the rogue when he is in melee range but otherwise pretend he doesn ' t see him . Rogue sneaks up , thinking he is getting a sneak attack when the Orc spins and slashes him hard with his scimitar .