Complex sentence: Lionel left young Lutessa (Tess) at an orphanage run by Granny Goodness, where she used her powers to suppress her memories of her true identity and was eventually adopted by the Mercers under her father's arrangements.
Split into simpler sentences: Lionel left young Tess (Lutessa) at an orphanage run by Granny Goodness, where she used her powers to suppress Tess's memories of her true identity. Tess is eventually adopted by the Mercers under her father's arrangements.