When Edwin was young he was mauled by a bear and was saved by a traveling septon. He spent the next eleven years of his life traveling with the man who saved his life, learning the ways of the seven.
Edwin returned to The Twins when he was one and twenty to advise his brother, lord Randyll Frey.
When Randyll left to fight Lord Marq Baelish at Harrenhal during the Ascent of the Lion, Edwin took command of the Twins, and when Randyll died, Edwin became lord of House Frey, as Randyll's children were believed to be dead.
Through a dream, Edwin found the valyrian steel sword Oath Keeper. Believing it to be a sign from the Gods, Edwin set out to reforge Oath Keeper and its sister blade, Widow's Wail.
After being declared Lord Paramount of the Riverlands by King Damon Lannister, Edwin set about his work. His goal was to feed the people of the Riverland's after the two burnings of the Ascent of the Lion, but without fields to grow essential grain he had to buy his food from The Vale, The Reach, and even Dorne.
It was during the second era that Edwin's nephew, Brynden Frey, returned. Brynden, the rightful heir of the Twins, was thought lost with his father at Harrenhal, but returned to claim his seat. Abdicating the title of Lord of the Crossing to his nephew, Edwin took the title of Lord Paramount to the newly vacant Harrenhal, where he established his court and began his rule of the Riverlands.
In the Spring Without Sun, Edwin focused on efforts to rebuild what had been destroyed in the Ascent of the Lion. The rains and the rampant bandits proved to be a serious hindrance to any visible progress and his vassals quickly became upset with his apparent lack of attention to the Kingdom. Growing more and more reclusive, Edwin spent much of his time in prayer at the sept of Harrenhal, eschewing court and other duties which served to only further anger his vassal lords. He received word of his nephew starting an alliance to unseat Edwin and claim the title of Lord Paramount for himself, which further drove Edwin into reclusion.
Edwin, worried of his nephew's ambitions, joined forces with a member of the faith, Septon Terrence, to whom he gave permission to form the Faith Militant. These forces quickly outgrew his reach, and he began giving them more and more allowances in order to keep them happy and loyal.
Near the end of the fourth era, Brynden Frey came to the Faith Militant with a better offer than his uncle could give. The septon and his men turned coat, forcing Edwin to give the Lord Paramountcy to Brynden and denounce all his titles. In return, Brynden gave the faith land and holdings in the Riverlands.
Randyll Frey, brother
Jeor Frey, brother
Bradamar Frey, brother
Jason Frey, brother