A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Author: Atarah al'Norahn
Otarin is one of the Heroes of the Horn .
Otarin appears when Mat blows the Horn of Valere outside of Falme and participates in the battle against the Seanchan. When Rand looks at the faces of the Heroes, he hears a hundred names to go with them, names that they were known by in other lives. One of the names that he thinks of when he looks at Otarin is Oscar.
(Reference: The Great Hunt, Chapter 47).