Skellig is deliberately ambiguous about its title character. The implication is that he is some kind of angel is obvious, but his general demeanour and attitude differ sharply from traditional ideas about angels.
The names "Skellig" and "Michael" are derived from the Skellig Islands off the coast of County Kerry, Ireland. One of them is Skellig Michael Island; St Michael is also the name of an archangel. The short text brings in so many ideas that readers and critics report widely diverse interpretations of "what the book is about". Short speeches on art, love, health, life and death, evolution, nature, Blake, education and family share a common context.
Almond has acknowledged the influence of "A Very Old Man with Enormous Wings", a short story by Gabriel García Márquez. Paul Latham compares the works in a research article, "Magical Realism and the Child Reader: The Case of David Almond's Skellig". Despite many similarities, he notes that Almond's child protagonists are much more caring and accepting than the close-minded and sometimes cruel adults in the Márquez story. Also, Mina and Michael keep Skellig a secret from the rest of human society. Thus the negative social commentary in Skellig, regarding medical institutions and other aspects of adult society, is not as harsh as in Márquez's story.
Mina also teaches Michael about the archaeopteryx a prehistoric bird from the dinosaur age. They also learn about persephone and the pomegranate tree thus wanting to name the baby that. It also shows that skellig produces owl pellets, suggesting that he is some kind of owl. all of this combined suggests that skellig is some kind of modern archaeopteryx a mix of owl, angel and relating to the story of persephone.