Burning Kor's mat states, "Players can only deal damage to Embers that are orthogonally adjacent to their mage tokens," and "Reduce to 0 all damage dealt to The Burning Kor by players not at the edge of the board." Since Xaxos: Outcast is not considered a player, these restrictions do not apply to him, and direct damage dealt by the Outcast ability cards can target any Ember or the nemesis. Note that this also means he can't split one damage instance between Embers.
