You attempt to bind a Celestial, an Elemental, a Fey, or a Fiend to your service. The creature must be within range for the entire casting (typically, summoned and trapped first). At the completion of the casting, the target must succeed on a Cha save or be bound to serve you for the duration. If the creature was summoned or created by another spell, that spell's duration is extended to match the duration of this spell. A bound creature must follow your commands to the best of its ability. If the creature is Hostile, it strives to twist your commands to achieve its own objectives. If the creature carries out your commands completely before the spell ends, it travels to you to report this fact if you are on the same plane. If you are on a different plane, it returns to the place where you bound it and remains until the spell ends.