We know of Robert, a fantastic warrior who fought with a heavy warhammer, defeated Rhaegar and won the throne. When it comes to Lyonel, he actually shares quite a few similarities with his descendant: a huge man (actually bigger than Robert, standing at nearly 6'11), powerfully built and who was considered one of the best warriors of his time, famed for his prowess in battle. Blud nick was "The Laughing Tempest" and he was excited to fight against the Kingsguard in a trial by combat, which hadn't happened in 100 years lol.
In general this is a great and competitive team. However they aren't winning this time around. On the other side Arthur Dayne with Dawn and his equal (in terms of sheer ability) Barristan Selmy. They both are just too legendary.
Arthur and Barristan grab that W.