Erza Mills is a major character in the 3rd season of Sleepy Hollow. He is also the father of Jenny and Abbie Mills, who left them when they were children.
When her and Abbie's mother's illness kicked in, Ezra couldn't handle it, and the only way he knew how to cope was to drink. He wound up joining the Navy both for the medical benefits and to sober up. He was shipped overseas and stayed for three-consecutive tours. By the time he returned, everything had changed. His wife was dead and his daughters were in foster care, but Ezra didn't step up and fulfill his fatherly duties. He knows it was a crappy thing to do, and he's regretted it ever since.
He was later seen near a tool shed where he met up with Joe Corbin. Unfortunately, he never heeded his warning to run as he transformed into the Wendigo set by an everlasting curse from the Hidden One. Jenny arrived later and they fled after they shot a tracking bullet. He then showed her a photo of Nevins and Joe to which he took and promised to answer all her questions after they deal with the Wendigo since he owed August so much. Tragedy struck as Joe could no longer be reasoned and Jenny accidentally shot him with a real bullet sparing her old man. Joe died moments afterwards. He later finds a tome in the Archives called the Elder Edda stating that if there was a clue in the Ragnarok myth, Twilight of the Gods, they'll find it in there. Unfortunately Pandora wasn't present and the Hidden One gave the team the slip into the FBI headquarters. And it was where Abbie sacrificed her soul to complete Pandora's Box and seal the Norse God.
He returned to the Archives and got the affirmation that Abbie was gone. The team confronted Pandora after Ichabod managed to find the Headless Horseman's skull thanks to the Blavatsy Map. With that, Death overpowered her then dissipated.
He was seen one last time at the cemetery talking to Crane after he mourned over her, saying there must always be two Witnesses at any given time, thus it was why they're called the Destroyers. If one dies, the soul's eternal and can't move on, meaning that Abbie's essence is within the next Witness chosen by her extended bloodline. The occupant being in Washington. He gave him a letter dating back to 1789, stating of the existence of a special organization known as Agency 355; although none of the occupants are bad, they tend to lose their way. Soon, the Assistant Director, Jack Walters, shows up with several men. Ezra takes off as Walters took Ichabod away to the District of Columbia itself. Ezra was never seen again.
The Missing Episodes of Sleepy Hollow[]
It was revealed before the events of Columbia that he was the one who convinced Gavin to move to DC with Jenny to find Crane. He always believed that he and Jenny, his only offspring, are capable of making great achievements, just like the Mills ancestors did. As well as finding the next Witness and carrying the torch and burdens of his bloodline.
He wasn't seen until a week after the Tribulations began and the Blood Moon rose. As promised, he stayed in Sleepy Hollow while Jenny and Gavin left for Washington, and they happened to meet him while they were about to round up a couple stragglers. He was with Sophie and Gavin's old man, Don Lucas, at a church who downright refused to relocate to DC and believe in the arrival of the apocalypse; however, it was Ezra alone who convinced him. Ezra was aware of all this, and by seeing Jenny's virtue of Faith he strongly believed that Jenny and Gavin are their only offspring that can make a difference and end the calamities using the help of the team. He stayed at that said church even when he met the Horseman of War who acted as a martyr, convincing the susceptible public that they cannot be saved by the Witnesses and the world will crumble under the apocalypse; however, Ezra kept the faith in them, as well as prayed for their success, including Jenny's and Gavin's.
He also managed to contact Jenny from the Church and told her that the entrance to Hell is located where the Tree of Fear exploded; the same spot where Abbie went to as the Shard of Anubis blew. Since Pandora's not around and the world is falling cause of Lucifer, it evolved into Hell rather than the Catacombs during the second Tribulation.