Brian (Uar/Uair)

In the tale Oidheadh Chlainne Tuireann (The Tragedy of the Sons of Tuireann), Brian is presented as one of the three Sons of Tuireann (with Iuchar and Iucharba). The three set out to kill their father's enemy Cian. Cian is the father of Lugh of the Tuatha Dé Danann; after Cian is killed, dismembered, and the crime concealed, Lugh imposes a recompense: the brothers must go on a quest fetching magical weapons. Their journey takes them "all around the known world" to obtain the items demanded by Lugh, a narrative arc that functions as a reparative obligation for kinslaying.

The examined manuscript and summary sources provide no physical description of Brian/Uar. The tale records actions and transformations (Cian into a pig; the brothers into dogs) but does not supply a direct bodily description of Brian in the cited material.

The narrative includes a shapeshifting episode in which Cian disguises himself as a pig and the three brothers take the form of dogs to pursue him; the tale thus records the brothers engaging in shapeshifting in that episode. Brian participates with his brothers in killing and dismembering Cian, in undertaking the long quest to fetch magical weapons for Lugh, and in returning badly wounded and pleading with Lugh for healing. In at least one version Brian is portrayed as the clever and subtle brother while his siblings are more easily overawed by him. Beyond these narrative actions—shapeshifting in the episode and success in procuring magical items—the sources do not attribute independent supernatural powers or invulnerability to him.