This article contains plot or ending spoilers.
Originally a mage, Garvin Usher lived in a small house on the southern edge of the Ridgewood with his wife and young daughter, and had a magical workshop in a cave further north. During an overconfident youthful effort to master a shard of the Mirror of Smoke and Dreams, he lost control of the magic, which warped and distorted the workshop around him... and had the same effect on his wife, who had entered unawares to bring him some food.
For the next three days, Usher worked desperately and futilely to undo what the magic had done. His wife was in constant pain, infrequently lucid. On the fourth day, during a rare lucid moment, she looked on him with love. He fed her calderleaf poison, putting her out of her pain, and renounced magic, returning home to tell his little daughter that her mother had drowned.
As Kaelyn grew up, Usher taught her to hunt and encouraged her friendship with a Grrrlf cub, Raal, whom he welcomed into his home like a second child. He was also on good terms with the Grrrlf packs that traveled through the Ridgewood, including becoming a personal friend of Raal's pack leader, Krrrfrrrlaaak.
When juvenile Wraiths appeared in the Ridgewood, Usher was forced to return to his distorted workshop and try to make sense of the creatures and find a way to stop them. He left a note for Kaelyn in his home, but fell out of contact with Krrrfrrrlaaak, who sent for Kaelyn and told her of his scouts' continued search for Usher when she arrived, as well as inviting both Ushers to attend his upcoming Harr-Quan ceremony.
In Chapter 5, Kaelyn and Raal find Usher in his workshop. Though surprised they followed him there after reading the note he left, Usher welcomes them both and finally tells Kaelyn the truth about his magical abilities and the death of her mother. After explaining the normal lifecycle of Ethereal creatures and the ancient outlawed art of fracture-jumping to travel through Etherea, he offers the progress he's made on the Wraith problem: a spell that enchants normal weapons to be harmful to Ethereans, though he claims the enchantment is temporary and wears off after repeated use. He had planned to test it himself, but now hopes his daughter and her friend, younger and stronger, will take on the mission.
After Usher applies the Wraithslayer enchantment to each sword and staff given to him by Kaelyn and Raal, he bids them farewell, asking Kaelyn if she doesn't have any word for her old father as she leaves. Kaelyn responds simply, "Goodbye."
If Kaelyn and Raal return before killing all the Wraiths, Usher asks them to stay and rest if they need to, and can enchant any further weapons they give him.
Speaking to Usher after killing all the Wraiths ends Chapter 5, and he appears only in the epilogue and Chapter 7 intro after that conversation. He congratulates them on destroying all five Wraiths, explaining that the stone circle they found was probably a circle of wardstones created to hold the Wraiths in but confused as to who might have set it in place, since he knows of no fractures to Etherea in that area. He struggles to stay on good terms with Kaelyn, who struggles on her part to understand and accept the secrets he'd kept from her, but thanks him for his support and seems less troubled than before.
When Kaelyn plans to leave immediately and get a few hours of travel in before dark, Usher asks her what's wrong, saying it's not like her to turn down a free meal and that being a mage doesn't change the fact that he's still her father. She says she'll keep trying to understand, and he confirms that's all he wants. In the end, she and Raal stay overnight.
On their departure the following morning, Usher gives Kaelyn a Protective Charm he'd made for her mother, and tells Raal he'll be honored to attend Krrrfrrrlaaak's Harr-Quan. Kaelyn asks if there's anything else he's keeping from her, and he says that being her father doesn't mean he has to tell her everything.