The god-folk of the successive invasions are "euhemerised", i.e., described as having dwelt terrestrially and ruling over Ireland in kingship before the age of mortal men (the Milesians, or their descendants). Afterwards, the Tuatha Dé Danann are said to have retreated into the sídhe (fairy mounds), cloaking their presence by raising the "féth fiada" (fairy mist). Having disappeared but not died, the deities oftentimes make "guest appearances" in narratives categorised under other cycles. (e.g., Lugh's appearance as the divine father and Morrígan as nemesis to the Ulster hero Cuchulainn; encounters of Finnian characters with dwellers of the sidhe; Cormac mac Airt's, or his grandfather's visits to the otherworldly realms.)