Aillen

Aillen, also known as Áillen mac Midgna, is a figure from Irish mythology, particularly known from the Fianna Cycle and the tale The Burning of Allen. He is portrayed as a malevolent being who annually burned down the royal hall of Tara, the seat of the High King of Ireland.

Aillen used his magical breath, likely involving fire magic or sorcery, to lull the inhabitants of Tara to sleep each Samhain (Halloween) before setting the hall ablaze. This occurred for nine consecutive years, leaving the kings of Ireland helpless against his attacks.

The hero Fionn mac Cumhaill is credited with ending Aillen's reign of terror. Upon joining the Fianna, Fionn was tasked with defending Tara. He used a magical spear, possibly obtained from the Tuatha Dé Danann, which awakened him whenever Aillen approached. Fionn then pursued Aillen and ultimately killed him, thus saving Tara from further destruction and earning recognition for his bravery and skill.

Aillen's actions represent a challenge to the established order and the vulnerability of even the most powerful figures to magical threats. His defeat at the hands of Fionn marks a significant moment in Fionn's early heroic career and solidifies his role as a protector of Ireland. His story is a common theme in Irish folklore of the time, involving supernatural elements, heroic deeds, and the struggle between good and evil.