Ramshackle[]
MC[]
Their first encounter happened during the ceremony held for welcoming the first years. Assuming Grim to be MC's pet, he reprimands them for bringing a pet to the school. Later, due to MC's involvement with Ace and Deuce, Riddle believes them to be a troublemaker as well. He also belittled MC for their lack of magical abilities and education.
After Riddle's overblot incident, he apologizes to his dormmates and MC for his actions, and their relationship seem to be on better terms afterwards. Riddle welcomes MC (and Grim) to Heartslabyul's unbirthday parties despite them not being dorm members, something that Che'nya points out as well.
In Riddle's voicelines, he states that MC, unlike other students, doesn't seem to fear him the slightest, while also adding that he doesn't mind it.
Grim[]
On their initial meeting during the ceremony, Riddle mistook Grim as MC's pet. He along with Azul are the ones who captured Grim, stopping his rampages. Riddle seems to consider Grim as a troublemaker.
Heartslabyul[]
Ace Trappola[]
They're both from the Queendom of Roses, but didn't meet prior to Ace's enrollment at Night Raven College. As a Housewarden, Riddle regards Ace as a troublemaker who tries to get the easy way out of work, but also sees potential in him.
Their relationship had a rocky start, with Ace breaking one of the dorm's rules soon after he enrolled, resulting in Riddle using his signature spell on Ace. It gets worse when in an attempt to make up to Riddle, Ace brings him a chestnut tart on an unbirthday party, breaking another rule and angering Riddle even further.
When challenged by Ace (and Deuce) for his position as a housewarden, Riddle believes it's a wasted time but goes along with the duel and wins easily. However, he's taken aback when Ace snaps at him and calls out Riddle's behaviour, to which Riddle reacts defensively and it also leads to him eventually losing control and overblotting.
Once Riddle comes to his senses he apologizes to Ace and the others, and after Ace states that a "sorry" isn't enough, he complies to Ace's demand and bakes him tarts as an apology.
After the events of Book 1, their relationship has improved, but they still get into small disputes.
In the The Phantom Bride event's story, Riddle is shown to have gotten accustomed to maneuvering Ace into a desired action, like when he compares him against Epel to stoke Ace's competitive spirit.
Deuce Spade[]
They're both from the Queendom of Roses, but didn't meet prior to Deuce's enrollment at Night Raven College. Riddle acknowledges that Deuce is serious and exemplary and that, unlike Ace, is trying his utmost hardest to meet the standards of both the dorm and the college despite his not-so-stellar grades and equally bad troublemaking tendencies.
He offers Deuce his old math workbooks with annotations written into them.[1]
Cater Diamond[]
Despite Cater's socialite personality being the polar opposite of his, Riddle never seems to get truly angry at him. When he found out that Cater's might be failing one of his classes, Riddle was determined to help Cater with his studies, despite Cater being a grade above him. However, when his first solution didn't work out for Cater, he decided to take a different approach. Knowing how much time Cater spends on Magicam, Riddle made an account solely to post study material on it in order to help Cater memorize them easier.[2]
Trey Clover[]
Trey is Heartslabyul's vice housewarden and Riddle seems to place great trust in him. They're also childhood friends and grew up in the same neighborhood in the Queendom of Roses. Trey, along with Che'nya, would bring treats and invite Riddle to play during his solo study sessions when they were young. However when Riddle was caught by his mother, Trey (and Che'nya) were forbidden from the Rosehearts residence.
When Trey was sick, Riddle decided to make soup for him even though he doesn't like to cook, partly because he felt responsible for Trey catching a cold.[3]
Riddle loves Trey's baked sweets.
Savanaclaw[]
Leona Kingscholar[]
During the events leading up to Leona's overbolt, Riddle tried to calm him down and told Leona that while he understands the irony of his statement, it pains him to see Leona in his current state.
Jack Howl[]
Riddle sees Jack as a capable and upstanding underclassman. It's noted by Ace that the two of them have similar self-ideals and work ethic despite looking so different from each other.[4]
Octavinelle[]
Azul Ashengrotto[]
Riddle holds Azul's talent and capabilities in high regard, but does not trust him. They've taken to tutoring Kalim together. After the events of Book 6, Riddle and Azul have come to see each other as friends, and sometimes feel comfortable showing their true feelings to one another.
Jade Leech[]
Riddle acknowledges that Jade is easier to deal with, but sees him as just much of, if not more, a threat as Floyd.
Floyd Leech[]
It's shown in the main story and vignettes alike that Riddle does his best to avoid Floyd, mostly for his relentless teasing and general disrupting, which often results in Riddle getting frustrated or mad with his antics.
Scarabia[]
Kalim Al-Asim[]
Riddle mentions that he has a hard time refusing Kalim, not only because Kalim rarely seems to listen, but also because despite coming across as pushy, Riddle knows his intentions are entirely pure.[5]
Riddle, along with Azul, tutor Kalim sometimes.[6]
As the scions of high-profile families, they seem to have similar sensibilities towards business situations. In the Twisted Halloween: Terror Is Trending event's story, as the NRC students muse how to drive the Magicamonsters off campus, Riddle and Kalim are the ones to suggest talking it over a meal.
Pomefiore[]
Epel Felmier[]
Riddle sees Epel as a boy with potential and plentiful resolve to achieve his goals.
Ignihyde[]
Idia Shroud[]
Riddle doesn't really hold animosity towards Idia, and just wants him to apply himself more as a housewarden that can lead his students with confidence.
Diasomnia[]
Malleus Draconia[]
The two respect each other as capable leaders who take initiative towards managing the members of their respective dorms. Riddle looks up to Malleus as a senior in grade, magical abilites, and nobility.
Sebek Zigvolt[]
They're in the Equestrian Club together; Riddle recruited Sebek during club day. Riddle's initial impression of Sebek when they first interacted was that he's arrogant, but saw that he was very diligent and cooperative towards those he respects and sees as important.[7]
Lilia Vanrouge[]
Lilia helped Riddle with cooking when Trey was sick and Riddle wanted to make him soup. Though he found some of Lilia's suggestions odd, he followed most of Lilia's instructions, showing that Riddle trusts Lilia's knowledge.[3]
Royal Sword Academy[]
Artemiy Artemiyevich Pinker (Che'nya)[]
Che'nya is Riddle's childhood friend from the same neighborhood in the Queendom of Roses. They used to play together as children, until Riddle's mother found out about it and deeming Che'nya (and Trey) to be a bad influence on Riddle, forbade the other two from visiting their house.
Though Che'nya is a Royal Sword Academy student, it seems that he occassionally pops up at Heartslabyul (mostly during tea parties) to pay his friends a quick visit; uninvited as pointed out by Riddle one time.[8]
