From Destinypedia, the Destiny wiki
The Ceded Knights are encountered during the Strength Test standing on arrow plates, they have no unique mechanics or abilities. However they are frozen and are unable to attack the player. During the test the player must interact with the Deepsight Orb to see which Knight they must kill first. After killing the first Knight, they must use the dead knight's plate to find out which one they will kill next. If you kill the wrong enemy, the rest of the Knights will leave their plates and become hostile, you will also be affected with Imbaru which will kill you in three seconds.