Fenoglio is a former writer, and the author of Inkheart.
Before encountering the Folchart family
Fenoglio wrote Inkheart, but before it could truly become worldwide popular, all the copies of the books gradually mysteriously disappeared, which discouraged him about doing something for the book to some degree.
Meeting his own creation
He was approached by Mortimer and Meggie Folchart at the village he lived in with his family as Mo came to see if he had a copy or original writings of Inkheart. Piecing together the information, Fenoglio figured out Dustfinger had been brought into the real world and was actually around, so he didn't care how he was advised against seeing the character he supposedly created, and met him anyways, along with Farid. Fenoglio caused Dustfinger to be severely distressed thus leaving with Farid.
He was then captured with Meggie by Basta and brought to the Capricorn's village, which happened to be not far from and just a short distance to where Fenoglio lived. There he reveals himself as the author of Inkheart to Capricorn only. To force Fenoglio to keep this secret, Capricorn threatened to hurt his two grandchildren. Fenoglio then helped Meggie during the time they were both taken captive; he wrote a new coda in which Capricorn and his monster servant, The Shadow, would be killed, which was then read aloud by Meggie and her father, Mortimer, turning fiction into reality. On the night of Capricorn's death, Fenoglio was willingly, transported into the world which he created.
Reencountering the Folchart family
Fenoglio had been living in the Inkworld for almost a year by the time Meggie managed to find him. He was found living in Ombra, in his landlady, Minerva's house and paid for his board by telling stories to her children, Despina and Ivo, otherwise he generally made a living as a poet. He purchased a glass man, Rosenquartz, who slept on Fenoglio's writing desk, and helped him ink his quills. He had actually been wishing for Meggie to arrive, and when she did, he wrote Cosimo the Fair "back to life", although it did not go quite as he planned.When Elinor arrives the Inkworld, Fenoglio grows to have a intense dislike to Elinor because wide source of knowledge.
Stepping up to the plate
Fenoglio was still a poet, but as he promised himself to never write again, he used poems from the real world instead of creating his own. Upon seeing the children of Ombra in danger, he participated in defending them with Meggie and deciding to write again.
Fenoglio is described as looking very much like an old turtle, and also described as being an elderly man with dyed-black hair and a wrinkly old face. However, throughout the events and witnessing some of the characters he created die in front of him, his hair became long and grey.