Lord Lyonel was an infant during the Dance of the Dragons, thus his mother Kyla Tyrell and uncle Robert Tyrell ruled the Reach as co- regents. His uncle Robert was judged likely to align the Reach with the House's "overmighty" bannermen House Hightower, but his mother Kyla chose instead to remain neutral during the war. As the war progressed, the bannermen were split, with men of the Reach fighting on both sides.
Ulf the White said Lyonel should be attained a traitor, since he had not taken part in the war. However Ulf desired Highgarden , Lyonel's seat, for his own and went on to die after the Second Battle of Tumbleton during the Dance of the dragons.
Since the Dance of the Dragons however he has grown into a competent fighter and a huge cynic. He is well known known for his harshness towards those who betray him. He is also considered to strict disciplinarian of the soldiers that he leads. Its because of his reputation for strict discipline among his men, that he became known as the Iron Rose.
He is also a renowned leader of cavalry. Thought to be due to hid experiences in the Targaryen Civil War he holds a great fear of Dragons.
Equipment & Weapons:
Noble Garments, and armour typically associated with most reach high lords. He wields a Rapier with an elaborately decorated rose hilt which twists around his hand majestically to offer protection to his hand.
He is known to be friends with Prince Viserys Targaryen, the current Hand of the King, and has strong relations to House Hightower, his most powerful vassals. He is said to be able to field the largest army in Westeros.
House Hightower of Oldtown: His most loyal bannerman due to his marriage to Lady Megga Hightower. Their levy is 30,000 men which include 20,000 infantry and 10,000 cavalry.
House Tarly of Horn Hill: Loyal to Lyonel as a result of his wife's mother being a Tarly. Their levy is 10,500 men which include 7,000 infantry and 3,500 cavalry.
House Redwyne of the Arbor: