Michael
Michael is an introspective and quiet boy who is nevertheless very good at soccer and intellectually curious. Over the course of the novel he changes, discovering his spiritual nature and his love of learning for its own sake.
Mina
Mina is an intense, mature child who has been encouraged to follow her own interests and curiosity. As a result of homeschooling, she has developed a passion for natural history and a great deal of knowledge in the areas of evolution, art, and poetry. Mina becomes Michael's best friend and confidant. She helps him to help Skellig and shares in Michael's experience of Skellig's special qualities and powers.
Skellig
Skellig is part man, part bird, and part angel. He has, apparently, been living in Michael's garage for some time, eating spiders and flies. Skellig is exceptionally quiet, secretive, and mysterious. At first, he speaks only in a squeak, complaining and making demands. Later, as he gains in strength and power, he engages Michael and Mina in strange, mystical dances during which they experience joy and feel the presence of phantom wings.