Finbar keeps a case for Skulduggery which contains a spare pistol, bullets, a spike bomb, and some other weapons. He always seems to be slightly absent minded and is constantly asking Skulduggery if he would like to say hi to Sharon at which Skulduggery reminds him he doesn't know Sharon.
In the third book, he helps Skulduggery to find the portal so he could know where the Diablerie intended to let in the Faceless Ones. He also tells Skulduggery that Sharon is pregnant and asks him to be the godfather. Skulduggery immediately declines, then takes Valkyrie Cain away from Finbar when he offers her a tattoo.
In Dark Days, Skulduggery and Valkyrie visit Finbar for information about visions that Sensitives have been having. Finbar asks if Skulduggery brought any souvenirs while Skulduggery was in the Faceless Ones' universe for his child, but Skulduggery says no. Finbar then takes the Skulduggery and Valkyrie to another Sensitive, Cassandra Pharos, who shows them the vision, which is about the end of world and Darquesse, the person who ends it. Finbar says that he has been having these visions as well.
Finbar gets a vision that a Necromancer is coming to talk to him, so he sends Sharon and their kid away. Solomon Wreath arrives and gets a Remnant to possess him and tell him whether Valkyrie is the Death Bringer or not. But the Remnant just gives him misleading information and tries to possess Wreath. Finbar remembers nothing about what happened when Skulduggery and Valkyrie ask him later.
Finbar plays a small role in the book. He is visited by Kenny Dunne, who is curious about a Sensitive who cannot see visions anymore. The Sensitive is Finbar, but he denies it. Thinking Kenny could cause trouble, Finbar tells Kenny that Geoffrey Scrutinous can tell him everything, but Finbar's true plan is to get Kenny to stop believing in the world of Magic.
In Kingdom Of The Wicked, Finbar is mentioned but not seen. The main part about this mentioning is that Finbar is no longer able to help Valkyrie and Skulduggery because he no longer has his powers. Skulduggery states, "The mind is a delicate thing." Finbar's mind was pushed too far in Mortal Coil, so he is no longer able to use his sensitive powers.
A man named Laken Cross is sent by the Supreme Council to kill Finbar. Finbar's powers were slowly recovering and he saw a vision who Cross came after him; he shot Finbar, then killed his wife and his customers, and finally shot Finbar twice more to assure he was dead. Finbar refused to allow his child to become an orphan, as Finbar himself was an orphan from the age of three, so Finbar sends Sharon and his child away and he poisons the handle of a mug. Finbar hands the mug to Laken Cross when he comes in. When Cross points a gun at Finbar, the poison takes effect and the gun falls out of his hand. As Cross dies, Finbar expresses his regret for having to kill him, but justifies himself, saying that Cross was an evil man.
Dying of the Light
He enters the Sanctuary, claiming that he has something important to tell Skulduggery and Stephanie. Later, he along with the help of Cassandra try to communicate with Valkyrie, revealing that she is still present in Darquesse's mind.
He makes another appearance when he and the other sensitives try to convince Darquesse that she has killed everyone on the planet, and is much more powerful than she really is.
Finbar is one of those loveable characters. He is often absent minded as is shown on multiple occasions including the time when he offers Valkyrie a tattoo. Finbar also takes a liking to a person very easily. His moods take control of him sometimes. He put a kitten tattoo on a man who wanted a tattoo of a jaguar on his back because he was in a kitten mood. He trusts other people and sees the best of everyone with the exception of Solomon Wreath whom he had a vision about. His wife is a part of a cult, and he still trusts her enough to have her as his wife. He shares a bond with Skulduggery (The Skull Man), and we don't know the origins of this relationship. Skulduggery knew Finbar well enough to keep the bomb in a very safe case before Playing with Fire.
He also is seen wearing a Pouges T-shirt which indicates he likes the band. He also listens to another artist with a popular song which is playing when Kenny comes to see him.
Finbar was a very powerful sensitive who was able to sense events prior to them becoming reality. However, he is able to miss some things, small or big, such as when Solomon Wreath managed to beat him by entering his house at the flip of a coin. He had known that Wreath would pay him a 'visit', but had no idea of the time. Finbar was physically weak and an inexperienced fighter as shown when he attempted to attack Wreath with a cushion. He later loses his powers after his mind was warped by the Remnant, which pushed his powers over the limit, and forced him to see too many things. He is not, however, permanently possessed by a Remnant like Tanith Low.
In Last Stand of Dead Men, Finbar's powers slowly begin to return, saying that he can occasionally see the future or read a mind. He believes that he will make a full recovery in given time, perhaps several months.