In Basque mythology, Mairu (pl: mairuak) or intxisu(ak), refer to giants who built dolmens or harrespil.
Origin
Mairu' means "moor" in Basque. This term is used with the sense of 'non-Christian' to refer to former civilizations or megalithic monuments. The origin of the Mairu is thought to be as old as the "mouros encantados" in Portugal (Spanish: moros encantados), who are thought to be the remnant of old pre-Roman deities.