You summon a fiend or aberration of challenge rating 6 or lower, which appears in an unoccupied space that you can see within range. The creature disappears when it drops to 0 hit points or when the spell ends. Roll initiative for the creature, which takes its own turns. It attacks the nearest creature on its turn. At the start of the fiend’s turn, you can use your reaction to command the creature by speaking in Void Speech. It obeys your verbal command, and you take 2d6 psychic damage at the end of the creature’s turn. If your concentration is broken, the spell ends but the creature doesn’t disappear. Instead, you can no longer issue commands to the fiend, and it becomes hostile to you and your companions. It will attack you and your allies if it believes it has a chance to win the fight or to inflict meaningful harm, but it won’t fight if it fears doing so would mean its own death. You can’t dismiss the creature, but it disappears 1 hour after you summoned it.