Aleister is a tall man. He has blue eyes, short, light blond hair and pale skin. He wears a white shirt, purple tie and a blue striped white sweater.
Aleister is a portly, well-spoken gentleman, but appears to be very materialistic and irritable, to say the least. He sees his peers as lesser beings than himself. Aleister appears to be very intelligent, which makes him rather compatible with fellow group member Grace, who he was getting close to up until his paternity was revealed. Owing to his "daddy issues" Aleister also finds trouble trusting people, and tends to only speak up when he feels his input is helpful, which is essentially all the time. He was one of the top five fencers in England, and was valedictorian.
Despite his betrayal, he refuses to let his henchmen gun down his former friends in Book 3, Chapter 3.
In Book 3, Chapter 6, his note to Grace shows that he feels genuine remorse for betraying the Catalysts and hopes to redeem himself, which he appears to do so by stabbing the Omega Mech, bringing back the catalysts after they were erased from time and let them escape.
Aleister respects Grace for seeking knowledge. He is hinted to have romantic feelings for her, as he grows quite flustered when the two are interacting. He seems to care a lot about how she sees him and doesn't want her to get into trouble. They continue to get closer until Aleister's secret is revealed, and Grace loses some of her trust for him. When you choose to encourage Grace to go to him after this and shout at him to listen to her, they share a kiss. And later when you go to Grace's room, he is there too. If Grace is left behind in the final chapter, Aleister will express sadness towards her disappearance; if you rescue her, he'll appreciate it.
in Endless Summer Book 2, Aleister is reunited with Grace (if you chose not to rescue her). When entering a secret place full of treasure, Aleister is hit by several darts containing a sedative that causes him to behave strangely. An example of this is when he supposedly hears music in his head and begins to waltz. He asks Grace to dance with him (diamond choice) and in the end they share a kiss after Aleister confesses his feelings for her.
In Book 2, Chapter 14, Grace viciously slaps him after he betrays the group.
His feelings for her are one of his main motivations for betraying you.
His Ember of Hope shows a future where they get married and have a son named Reginald.
He originally states that Your Character, and many others, are idiots and simpletons. In Chapter 4, if he/she sprays the chain to the release valve with the gas from the fire extinguisher to brittle the metal, instead of bashing it,you will manage to impress him. He goes as far as to say that Your Character isn't as dumb as he originally thought. In Chapter 13, when Your Character finds out that he is a Rourke International Asset, the college student can choose to call him a liar and that he/she doesn't trust him.
After his betrayal in Book 2, Chapter 14, you can choose to either forgive him and surrender peacefully, or put up a fight and spit in his face.
His Catalyst Idol shows you furiously confronting him in the Elysian Lodge for selling out their friends to Rourke, which ultimately led to their deaths. In a homicidal rage, you defenestrate him.
When you confront him to save Sean and Craig in Book 3, Chapter 3, he begs you to walk away. When Sean tries to convince him to betray his father and make amends, you can choose to agree that Aleister deserves a second chance or state that he'll only betray you again.
While this isn't revealed until Chapter 13, Aleister is Everett Rourke's son, and despite being named after him, Aleister feels nothing but contempt for his father. This is because Rourke had been absent for a large portion of Aleister's life. According to Aleister, on his 10th birthday and the day of his graduation from high school, Rourke was abroad on both occasions. In fact, the whole reason Aleister is on the island to begin with is because he wanted to confront his father and cut ties, but Rourke was under the impression that his son was looking to make amends. Aleister eventually betrays you in Book 2, Chapter 14, and joins his father, stating that he is a genius and starts to see his plans in a positive light, acknowledging that he is evil but that he offers the greatest chance of survival.
In Book 3, he is shown carrying out his father's orders. However, it is mentioned that Everett lied to him and told him that the rest of the Catalysts had been killed during an escape attempt. He lashes out at Everett in Book 3, Chapter 6, for manipulating him into betraying his friends, going as far as to call him a "scared, petty, little man".
Aleister dislikes Jake because he doesn't agree with Jake on many issues. An example of this is when Jake guesses that the Sabertooth is from the Jurassic Era, but Aleister becomes enraged that Jake was "only 140 million years off" and states that the sabertooth is fact from the Pleistocene Era.
In Book 2, Chapter 14, after Aleister betrays the group, Jake becomes extremely angry at him and starts disliking him even more.
In Book 2, Chapter 8, it is revealed that IRIS is the artificial intelligence of Aleister's deceased mother. Ever since, Aleister is shown to trust her and refuses to believe that she is leading them into a trap. His father's promise that he can bring her back to life was one of the main motivations for his betrayal.
In Book 3, Chapter 9, it is revealed that she isn't Aleister's biological mother and she cloned him from Rourke's DNA.
- Aleister is annoyed to discover that Your Character has a higher threat rating than him.
- His Hadean Zodiac sign is Serpens, the Snake.
- Jake calls him "Malfoy" because of his white hair and his ego.
- The Pavo Catalyst idol reveals a timeline where he dies and Michelle blames herself for his death. The Serpens idol reveals a presumably different timeline in which Aleister was the last of the group to die, defenestrated by Your Character in revenge for causing the deaths of everyone else in the group.
- He apparently speaks French as he understood Yvonne when she spoke.
- He is a skilled piano player.
- It is implied that he is studying Law/Criminal Justice at Hartfeld, but his flashback suggests he is planning to attend business school after college rather than law school.
- Aleister's actions have divided the fandom: some fans support Aleister's decision to betray you, stating he's looking at the bigger picture, while other fans are as furious with him as the rest of the group, stating the crimes he's committed are unjustifiable, and since he was the most intelligent, he should've known his father was manipulating him.
- Prior to his betrayal, he was still considered the most disliked Endless Summer protagonist. Several fans were put off by his narcissistic and condescending attitude, as well as his sarcastic and flat-out rude comments.
- The Embers of Hope collectibles imply that he may betray his father and redeem himself. This was proven correct in Book 3, Chapter 6, when he destroyed the Omega Mech and escaped with the catalysts.
- His crimes include being an accessory to murder, three counts of kidnapping as well as aiding and abetting Rourke and the Arachnids.
- His Ember of Hope shows a future where he is married to Grace and they have a son named Reginald.
- The writing for Aleister's character is inspired by the song, Prodigal by Porcupine Tree.
- Aleister in alternate timelines:
- Aleister's and Michelle's bodies were switched due to a device called Freaky Friday Device created by Everett Rourke inspired by his favorite movie, Freaky Friday.
- He and Lila were lovers.
- He fenced with his father on a burning building.
- Taari called him Uncle Al.
- It is implied that he murdered Quinn and Diego after the former accidently caused Grace's death.
- According to Pixelberry's "Endless Summer Finale" blog, he was originally depicted as a serial killer.