Ancient Celtic pagans believe that, during Samhain, the gates between Earth (or the Middleworld) and the “Otherworld” open, allowing faeries to pass through.
In Ireland, Aillen — a fire-breathing faerie deity and musician — wreaked havoc on the sacred Hill of Tara for many years. He’d play his harp to lull his victims into a deep sleep before incinerating the hill with his fire-breath.
The 1914 portrait above, Heroes of the Dawn, depicts Aillen’s eventual demise at the hands of Irish mythological hero Fionn mac Cumhaill.