Where you Meet Winfield:
You meet Winfield in Rome Valley at level 7.
A man with a strong desire to gain power. He comes on a little strong but he has a strong sense of justice and knows right from wrong, he'll offer help with no question asked.
You first actually 'meet' Winfield with Zerva in Zenzagun Fort, though his name is filled with question marks. He flees and you get Zerva in your party. But you don't officially
meet this man until Rome Valley for him to join your party to fight the Black Knight, the same Knight that nearly killed protagonist Leonhardt in the very beginning of the game.
He runs into the party again during his quest for revenge; the Gridamas Invasions killed his family and a significant other, so he went to Erin for power to get his said revenge. In Erin a forbidden power rests: The Bracelet of the Covenant, which was hidden and sealed there. Winfield went after the bracelet because legend says it would grant absolute power to the one who wore it.
But Winfield failed to fully grasp that the legend also said it believed to also be the key of awakening a very powerful evil. Yet he still broke the seal and and took the bracelet, knowing the consequences (at least somewhat) but did it regardless. His actions lead to Summerill awakening and regaining his power once more.
Winfield gained his great power, but at a terrible cost. It was cursed. Any time he tries to use the power he obtained, the curse of Summerill would give his body pain, pain more hellish than anyone could fathom.
Eventually, the curse will turn Winfield into a monster.
He was informed by Dyshana that the only way to break the curse is to either replace the seal on Summerill or break the bracelet and repent, a much more difficult task since the bracelet cannot be removed. He decides to fight Summerill to repent and fix what he's done in order to save himself from his monsterous fate.