Tadhg is a Terram expert who hails from an older Irish magical tradition that was closely involved with the various faerie factions, and that found itself adopted into House Ex Miscellanea rather than Merinita when the Order spread to this territory (although with his eccentric mutterings, some may mistakenly assume that he is Criamon instead).  Longivans ex Merinita recruited Tadhg to join the nascent covenant when it was first being established; before that, he had been at the covenant of Lough Derg, on the border between the provinces of Connacht, Munster, and Meath.  The two of them developed a strong friendship since then.  Apart from this, Tadhg is reclusive even by wizard standards.

Tadhg's long, white hair and beard and giant-blooded build make him look about 70, but a healthy 70.  He can occasionally be spotted leaning on his heavy staff, but has no problem without it.  He favors drab clothing, and also wears two brass rings set with colorful stones.