One of Grubbs' ancestors, the magician Bartholemew Garadex, discovered that the demon master Lord Loss possessed the ability to cure the curse. Bartholemew summoned him to ask for such a favour, but in keeping with his demonic nature, Lord Loss had no interest in performing any such charitable act. However, Bartholemew discovered that the demon master possessed an obsessive fascination with the game of chess, and managed to strike a deal: Bartholemew would teach Lord Loss to play the game, but each time the demon master was bested by him, he must cure one infected Garadex.
After a time Lord Loss grew impatient with this arrangment, as Bartholomew would only play when he wanted a family member cured. After Bartholomew died, if a family member needed curing then two members of the family would be chosen to face Lord Loss at a midway point between the human universe and the Demonata universe. One would fight Lord Loss's familiars and the other would face him in five simultaneous games of chess. If they could win three of the games, the curse would be removed, but the one who faced Lord Loss in chess would fight him alone in the Demonata's universe. If they lost the chess match or the fight with the familiars, then Lord Loss would be allowed to kill all involved.
Grubbs then moves in with his Uncle in Carcery Vale and befriends a child called Billy Spleen, (who prefers to be called 'Bill-E'). This boy reveals that the reason he often spends time with Dervish is because he thinks that he is actually Dervish's son. After looking through books and noting Dervish's behavior, Bill-E and Grubbs begin to suspect that Dervish is a werewolf, but when the two of them follow him into the woods, Grubbs discovers that Bill-E is the actual werewolf. Dervish tells Grubbs that he always knew Bill-E was a werewolf, as Bill-E is Cal's other son. He also explains to Grubbs about the family curse, the nature of Lord Loss and the other Demonata, and the perilous battle which they must undertake in order to save Bill-E .
They summon Lord Loss into the cellar of the house, where Dervish confronts the demon master in a game of chess while Grubbs fights the familiars. Half way through, Grubbs is struggling and due to Lord Loss's fondness of him, he decides to bend the rules this once and allows Grubbs to swap places with Dervish. Initially, Lord Loss beats Grubbs easily, but once Grubbs realizes that the demon feeds off his discomfort, he manages to gain the upper hand by behaving in a calm and happy fashion. This allows Grubbs to win the chess match, resulting in Bill-E being cured and Dervish going to the Demonata universe to fight Lord Loss alone. When Bill-E comes to, he doesn't remember turning into a werewolf, so Grubbs lies to him saying that Dervish has been cured but is under a spell to keep him calm. Dervish's body continues to function in the normal universe but with no discernible personality, as his soul is still fighting Lord Loss. After many months, Dervish returns, seemingly well and unharmed.
In Slawter, when Grubbs is about fourteen years old, horror movie producer Davida Haym offers Dervish a chance to work on the set of her new movie, "Slawter", which is about demons. He quickly accepts the job, thinking that it will be a good chance to help him recover from his battle with Lord Loss, and he and Grubbs move to into the town in which the film is set. Grubbs soon finds out that Davida has made a deal with Lord Loss, promising to bring Dervish and Grubbs to work on the movie in exchange for being allowed to film the Demonata for her movie. Dervish, Grubbs, Bill-E and the psychologist Juni Swan attempt to flee the town, but strike a barrier which sends them into a dream state. After waking, the Gradys and Bill-E run into the town trying to warn people to get away, claiming that there is a gas leak which will soon cause a catastrophic explosion.
No one heeds their warnings and Davida sets the Demonata upon the unsuspecting cast and crew. However, Lord Loss betrays and kills her. Using Bill-E as bait, they lure a demon close to the invisible force field that surrounds the town, then explode it to create a hole through which to escape. This done, Grubbs finds himself forced to battle multiple demons with power he never realised he had in order to buy time for the people to get through. An unlucky few are still trapped inside, left for the Demonata to slaughter. After escaping, they see Davida's assistant director sitting on the ground; Bill-E stops Grubbs from harming him, but when Juni arrives, she kills him with magic she discovered behind the barrier. Back at Dervish's house, Dervish scans Grubbs for any sign of magical power. Grubbs unconsciously hides it from him, but later discovers that he does indeed possess magical powers even away from the Demonata, confirming that he is a magician.
Along with Bill-E and Loch, Grubbs decides to go looking for Lord Sheftree's treasure, but wakes one night to find himself moving rocks away from the hole which they had dug. Bill-E accidentally stumbles upon a tube leading to a cave full of stalactites and stalagmites with a large waterfall. They start looking for the treasure but find none. Bill-E and Loch decide to climb a wall of the cave. At this point, Grubbs begins to feel very ill (possibly because of the full moon) and looks to the floor of the cavern. He sees a girl's face in the rock similar to his sister's, whispering in a strange language, but then she suddenly goes silent. Grubbs hears a scream from behind him, and turns to find Loch's lifeless body lying on the floor, blood seeping out of his head. Grubbs attempts to heal the wounds while Bill-E leaves to get help. While Bill-E is gone, Grubbs needs to resuscitate Loch several times. The first two times it works, but then on the third, Loch stops breathing, his heart stops beating, and he dies. The whispering starts again, startling Grubbs. When he calms down he looks at Loch, and lifts up his head and notices something odd - all the blood is gone.
Eventually Dervish and Bill-E turn up at the cave, however there is nothing that can be done to save Loch's life and Grubbs soon realises that there is no ambulance. At Dervish's insistence, the three move the body to a nearby quarry and throw it over the edge. Dervish explains that the cave is the former site of a tunnel to the Demonata's universe (the same cave from Bec). Dervish has been given the duty to protect the cave and make sure nobody else can unleash the Demonata.
Returning to school, Grubbs discovers that the psychologist has left and a new one has come as a replacement. He is sent to meet her and finds that it is Juni Swan. She helps Grubbs, Bill-E, and their friends to cope with Loch's death, and soon everyone seems to be fine. However tensions increase as Juni and Dervish become romantically involved, and they eventually move in together. In the following days Grubbs becomes more aware of the impending doom of his curse. Not only that, but he begins to notice a tramp coincidentally appearing around Carcery Vale. The tramp implies that Dervish may have called the Lambs to kill Grubbs, and Juni confirms his suspicions. However, she also tells Grubbs that she sees him as her own son, and will do whatever it takes protect him.
At Grubbs' insistence, Dervish locks him in a cage as his lycanthropic transformation worsens. While he is in the cage, Juni suggests that Dervish should leave while she performs a dangerous spell to help Grubbs. Once Dervish is gone, she frees Grubbs from the cage, then passionately kisses him when he shows his desire to die at the hands of the lambs, claiming that she will not let him be killed while there may be hope. She says that they should go to meet up at the cave. He then breaks out of the cage, and battles three of what he believes are Lambs, dispatching them easily. Grubbs runs to the cave, where he loses control again and turns into a werewolf. When he returns to his normal state, Grubbs finds that he has killed Ma & Pa Spleen, Bill-E's grandparents and legal guardians. Not wanting to kill again, Juni says that the two of them need to run away from Dervish and the Lambs to protect Grubbs, both from his own death and the deaths of others.
The two of them board an airplane, on which Grubbs falls asleep. When he awakes, the cockpit opens and demons appear on the plane, Artery first and then the scorpion-like creature from the front of the book, along with another rabbit-like demon. They begin killing the passengers on the plane. Finally, Lord Loss appears, stunning the passengers. Juni appears next to him and reveals that she summoned him and is actually an agent of Lord Loss. Grubbs is saved just in time by Beranabus and they both jump from the plane, flying to a cave in a desert which is a cave closed by magic. There Grubbs meets Kernel Fleck, who appears disdainful of him, and discovers that Juni was the one who killed Bill-E's grandparents.
Beranabus convinces Grubbs to go to the Demonata's Universe, but when faced with danger, Grubbs flees back to the cave where he waits seven weeks for them. After they return, Sharmila arrives at the cave and informs them that demons entered through the tunnel and are being organised to take land as well as kill. Beranabus realises that this is what Bec was trying to warn Grubbs about. The four take Sharmila's private jet to meet the remaining Disciples at Carcery Vale, where they plan to enter the cave and destroy the tunnel. Beranabus, Kernel and Grubbs head directly to the cave opening while the others battle demons. Lord Loss appears and taunts Grubbs by showing him the heads of his uncle and friends, however Bill-E is not there. Bec appears in the ground at Grubbs' feet and they connect hands, and tpgether they create a magic barrier to protect them from the demons. When Kernel joins them the three form the Kah-Gash (a weapon that can destroy a universe), and somehow travel back in time to the night the tunnel was opened.
Inside the cave Bill-E and Dervish are being held prisoner by Lord Loss, Juni and his familiars. As Juni performs the spell to open the tunnel, Beranabus, Grubbs and Kernel battle the familiars. Grubbs frees his uncle and brother, who now knows of his true parentage thanks to Lord Loss' tauntings. Juni's glamour is wiped by Beranabus and she is revealed to be Nadia Moore, who had joined Lord Loss in Demon Thief. Dervish battles with Juni and kills her by dropping her on a stalagmite. However, the spell is not broken, leading Grubbs to the realisation that Bill-E is the "key" to the tunnel's opening, due to his unintentional sacrifice of Loch (as Loch clung on to the rock, Bill-E had offered his hand, but whipped it away just as Loch plunged to his death). Grubbs makes the hard decision to kill his brother to stop tunnel from opening. Bec enters Bill-E's dead body (she had travelled back in time inside Grubbs) and casts powerful spells destroying Artery and Spine. Lord Loss flees, taking Juni's body with him.
Bec transforms Bill-E's body into her own and is reunited with Beranabus, whom she had known as Bran when they first met in Bec. Beranabus reveals that he is a half demon, and battles with that evil side of himself every day, just like Grubbs has to fight his inner werewolf. Grubbs joins Beranabus and Kernel in the Demonata Universe, leaving Bec to catch up on the last thousands of years and look after Dervish.
In Wolf Island, Grubbs is both the primary character and the narrator of the story, following on from where Deaths's Shadow left him off.
Some people have magic within them, however it usually remains dormant unless the person sees something magical like a demon attack, or uses magic in an area where lots of mystical energy is present, and they become aware that they have powers. From this the Disciples, (others that have become aware of their powers and answer to a magician known as Beranabus), can contact the person that has become aware and attempt to recruit them in to the ranks of the other Disciples to travel around the world and stop demons from passing into our Universe. Some people choose not to get involved and some do.
Most of the Disciples have very limited powers unless in the presence of the Demons or in the Demon universe. However, Grubbs managed to disable large security flood lights and turn concrete blocks to mud-like sludge so they can be scooped out of a wall in Slawter. However, there were demons closeby at that point, so he may have been tapping into their magic. He does a few spells that are average in power but near the end creates a barrier that demons cannot pass, something which Dervish could not do. At first Grubbs believes he was only able to use magic in the presence of demons but at the end of Slawter he tests his powers, when not in the presence of demons and finds that he can make his reflection disappear and change light. Only a few people can use magic outside of the demon universe, and to be able to do it without training means that Grubbs is extremely powerful and is also a magician. Beranabus confirms this in Demon Apocalypse, while the two are falling to the ground after being attacked on the plane by Lord Loss, and Grubbs proves him right by flying to ground with Beranabus.
He has shown great cunning, emphasized in his chess match with Lord Loss. When he realizes that the demon master is feeding off his disappointment in losing pieces, he puts on a happy facade and defeats him. Although he wasn't as good at chess as Lord Loss, he confused the demon which caused him to make mistakes.
He also has the power to fight off his own wolfen gene, which no other Grady has done before, and is able to retain at least a certain degree of awareness when he turns into a wolf.
Due to this potentially immense power, it is confirmed Demon Apocalypse that, like Kernel Fleck, Grubbs is part of the Kah-Gash when, in that book, he, Kernel and Bec link hands and travel back in time.
He also has the power to change his form freely from human to werewolf and even a mixture of both, as seen in book number 8 "wolf island" where he changes into a werewolf to save the group from being eaten but changes part of himself to human again to communicate with the humans of the group. Grubbs states, however, that he prefers being part werewolf/part human to being fully human. This is because he can be with his family (Grady's who have been affected with lycanthropy) and his human friends, and communicate with both.