Who is Ariel from A Tempest: Based on Shakespeare's The Tempest, Adaptation for a Black Theatre and what is their importance?

Ariel is the sea nymph that Prospero enslaves after he frees her from Sycorax. Ariel aids Prospero in the sinking of the nobles' ship to sink, and personally adds to the torment of the nobles after their arrival on the Island. Prospero frees her the day before the noblemen set sail for Europe as a reward for her services.