edit Before the series
His first name is Fernald, yet his last name is unknown, though he does state that it differs from that of his stepfather, Captain Widdershins. Before joining with Count Olaf's theatre troupe, he and his sister Fiona lived with Widdershins on his submarine, the Queequeg. However, after growing tired of Widdershins’ constant nautical ejaculations and bossing around, Fernard eventually flees the submarine where it is revealed he took up a life of crime with Count Olaf. It is unknown how or when he lost his hands. Throughout most of the series, he conspires with Count Olaf to steal the Baudelaire fortune. Olaf himself does not refer to Fernald by his proper name; instead, Olaf and Esmé call him "Hooky". One of his aliases is O. Lucafont, an anagram of Count Olaf.
edit In the series
In several books, he appears in various guises to aid Olaf with his plans; his hooks are always hidden in these attempts.
In the second book of the series, The Reptile Room, he disguises himself as Dr. O. Lucafont and arrives at Dr. Montgomery's house after receiving a call that there had been an accident. In the end when the adult characters finally realize who Count Olaf really is, "Lucafont" claims he will take Olaf to jail. Although Sunny Baudelaire bites Fernald's fake hands off before he can escape unexposed, the two men still flee the scene.
In the sixth book of the series, The Ersatz Elevator, he disguises himself (with extra-long jacket-sleeves) as the doorkeeper of 667 Dark Avenue. Still maintaining his façade, he bids on (and wins) the statue in which the two Quagmire siblings are hidden.
In the eleventh book of the series, The Grim Grotto, he is reunited with his sister Fiona, who, along with their stepfather Captain Widdershins, is working with the Baudelaire children. After Widdershins mysteriously disappeares and the Queequeg is damaged, Fiona considers her brother to be her only family member left, and seemingly joins Count Olaf's troupe to stay with him.
Sometime later, though, Fernald and Fiona betray Olaf by stealing his submarine. They meet with their stepfather again (who, in the words of Kit Snicket, "had forgiven the failures of those he had loved") along with Kit and Phil to help repair the Queequeg and aid the Quagmire triplets and Hector in their self-sustaining air balloon.
However tragedy stikes, and trained eagles popped the hot air balloon, sending them crashing into the Queequeg. Stranded on the wreck, they see the mysterious question mark (an ambiguous shape that the Baudelaires had encountered on the radar screen that scared even Olaf) reappear. Although Kit is terrified of what she referred to as The Great Unknown, the others want to take their chances confronting it. The mysterious shape takes Fernald and the others away, its intentions and results still undescribed.
edit Good or evil?
The Hook-Handed Man has shown remorse and doubt regarding his crimes, and states that there are no such things as good people or bad people, that every person is like "a chef's salad with good parts and bad" arguing that good people often do bad things while bad people may do good things. He has shown love for his sister.
Count Olaf says in The Penultimate Peril that "Hooky and Fiona double-crossed me yesterday". This implies that Fernald has left Olaf's troupe. Notably, he is the second-last of Olaf's assistants and conspirators to leave, the last being Esmé Squalor.
In an interview with author Daniel Handler, the interviewer inquired why, in the last couple of books, the line between the good people and more treacherous ones seemed to have become a bit blurred. Handler responded, "It's sad isn't it? I think the Baudelaires are getting older, and one of the sad facts about getting older is that you've always thought of yourself and people you know as righteous and true and the people you dislike as evil. The older you get the more muddy that water becomes".