Their Overworld is the perpetually green Tír na nÓg, which is besieged by Crom Cruach, the Greater Titan of Earth. Their original Underworld was Mag Mell, the Plain of Joy; when it was transformed into one of the terrae incognitae by Titanic magic, they bargained with Gwyn ap Nudd, lord of Annwyn, the Welsh afterlife, to acquire a portion of the land as their new Underworld, Tir na Marbh.
The Tuatha were actually the fifth major group to come to and rule over Ireland; previously, it had been led by humans and Titanspawn. In the end, it was a group of Titanspawn native to the land, the fomorians, who had to be conquered before the Tuatha could claim the Green Isle for their own, a battle fought using wits and seduction almost as much as actual warfare. Even today, they still struggle against enemies to keep their beloved country safe, especially the fomorians, who have sworn to destroy the Tuatha and reclaim Ireland as theirs.
Of the main Pantheons, the Tuatha bear a marked resemblence to the Aesir, holding similar values of nobility and honor, but tempering them with artistic merit and beauty. The Tuatha are also Fate-obsessed; however, unlike their Norse cousins, they have no deity that has a direct line to foreseeing or controlling Fate. The gods of Ireland instead try to temper their odds with Fate by using geasa, personal vows and sacrifices, to nudge it in the direction they want it to go. The Tuatha, however, are much more confident in spite of being tormented by their Fate, and have an overconfidence that could even give members of the Dodekatheon pause. They are known for their boisterousness, loud battle cries, and frontal charges in battle; the idea of stealth or a sneak attack is an alien one to the Tuatha.
Their rowdy natures made the more refined Pantheons a bit reluctant to work with them at first, but their honor in battle has endeared them to almost all of them. The Tuatha who choose to fight along Scions of other Pantheons will usually find ready allies among all of the main Pantheons, save the Atzlánti; the sacrificial nature of the Mesoamerican Pantheon puts most of the Tuatha off, as it reminds them of the Titanspawn they spent so long exiling from Ireland.
The Tuatha tend to push their Scions, not out of manipulation or cruelty, but because they believe their offspring are capable of so much more than they think they are. They are also one of the most generous Pantheons when it comes to Birthrights, but should a Scion dishonor themselves or fail in their duties, their godly parents have no qualms about taking them away.
- Aengus: God of youth and love.
- Brigid: Goddess of healers and smiths.
- The Dagda: Warrior and former king of the Tuatha.
- Danu: Goddess of creation.
- Dian Cécht: God of healing.
- Lugh: God of versatility.
- Manannán Mac Lir: God of the sea and ferryman to the underworld.
- The Morrigan: Goddess of violence and fertility, and a powerful seer.
- Nuada: King of the Tuatha.
- Ogma: God of learning.
- Irusan: God of cats.