After Marinette contacts Master Fu, Adrien learns that Plagg is his kwami and that he can’t transform without him however, he is happy to see Plagg when he returns. In «Syren», having enough of secrets, Adrien decided to quit being Cat Noir, which left Plagg very nervous, if he didn’t tell him what Ladybug was hiding. When Plagg admitted that he was also his close friend, Adrien smiled at the compliment. Despite Plagg’s flaws Adrien is happy to him in his life, mentioned in «Plagg «. During «Frozer», he once again tries to confess his love to Ladybug, but once again, she rejects him becoming sad.
The Other Kwamis
Until it was ruined by an akumatized Kagami that was convinced that Marinette was a manipulator and he rushed to her defense then once their friend was deakumatized they cleared things up. After that he takes things slow with their relationship believing they have all the time in the world. Losing them, Marinette was brought to Fei’s home, seeing that she was on her own as well as going through her own hardships. When found by Cash again, she was crushed to know that Fei was the cause of her «misfortune», even doubting if they were friends. Spotting an akuma, despite not being completely sure of Fei’s intentions, Marinette refused to leave her when she needed to transform into Ladybug, telling her that she is one of the good guys.
However, a huge mishap led to Adrien returning home, he apologized to Marinette for her efforts to get him to New York and wouldn’t have minded staying longer with her. During the plane ride home, Adrien received a surprise picture of his friends and smiles. In «Battle for Miraculous», he was happy that Marinette and Kagami were getting along.
Despite having and being cordial with Cat Walker she couldn’t get Cat Noir out of her mind. At first, hastily believing he was akumatized hurt over renouncing his ring and being replaced. Not wanting to repeat herself she tried to include Cat Walker but it didn’t go so well. Accepting it was a sentimonster, she berated herself for not understanding him or doing nothing when he left calling herself «the worst guardian ever». During their adventures in New York, still reeling from the sadness and shock of what happened to Uncanny Valley, Ladybug was devastated to discover that Paris is wrecked and there was nothing she could do. Hearing Cat Noir take full responsibility for everything, she was tearfully shocked when he renounced his ring and left.
Miraculous contains multiple minor supporting characters who are pretty clearly intended to be in same-sex relationships, even if the show doesn’t ever come out and say so explicitly.
After Adrien gets his memory erased by Oblivio and detransforms, he meets Tikki. He admires her compliment when she calls him and Marinette an effective couple. When Oblivio was defeated and his memory was restored, he forget about their encounter. During «Feast», he receives a letter from Wang saying that he took his Miraculous back in order to protect him from his old sentimonster. Despite being powerless, he and Ladybug used their creativity to distract the creature.
Family
Hearing Fei mentioning her father’s teachings, Marinette guides her in the right direction to fully understanding the dragon’s value in which she was saved. Afterwards, Marinette saw Fei had passed another test, reprimanding Cash for his actions. Later, they celebrate Marinette’s great-uncle’s 60th birthday as friends and honorary sisters. When the heroine knew of Mayura’s deception with how to delete CatholicSingles profile a sentimonster of her in «Ladybug», she finds a way to flush her out. After setting her sentimonster counterpart free, she is horrified that Mayura destroyed her, despite being a living creature. During the fight, she notices Mayura’s weakened state and catches her, but seeing Cat Noir in the same predicament, Ladybug releases her, knowing she can get her Miraculous another day.
Season 5
After Veronique’s deakumatization and Marinette departure, Adrien was asked by her if he found out his answers to which he replied yes. Adrien treats Kagami respectfully as an opponent during their match in «Riposte», and he feels guilty for his uncertain win against her, making her depressed. Though he isn’t initially aware that Kagami is a girl or that her family is famous for fencing, he treats her kindly, and he encourages her to try again, offering her a rematch with a definitive winner.
During «Heart Hunter (The Battle of the Miraculous – Part 1)», Marinette spends time with him and Kagami at the Borgeuois wedding anniversary. Seeing Adrien getting along so well with Kagami, she gives up her romantic pursuit of him so he can be happy. After Hawk Moth’s and Chloé’s respective defeats, she enjoys ice cream with him and their friends.
She enjoys hanging out with her on several occasions seen in «Gorizilla», «Captain Hardrock», «Syren» and «Frightningale». Under the effects of Simpleman’s powers, she was stopped by Chris and his friends and after following their lead in deakumatizing Rolland as Ladybug, she praised the young ones for saving them. Heartbroken about how her love relationships cost her everything, a depressed Marinette believed that Master Fu made the wrong choice in choosing her as a Miraculous holder or guardian in «Transmission».
Her only weakness, out of everything in the world, comes from her intense feelings for Adrien. As she matures, she learns how to better control her feelings and not let them get in the way of responsibly using her powers. However, she is still a teenager after all, so it’s only natural that she would slip up and let her emotions get the better of her every now and again.
But upon soon finding out their Monarch’s deception she and Grimalkin ceased their fighting and fell in love but were branded traitors then fled their horrible fates, relinquishing their jewels and left into parts unknown. Hearing of the kwamis’ capture in «Multiplication», he harshly demanded the heroes explanation. But before he could scold them any further, Ladybug and Cat Noir scolded Su-Han back about the progress they made, finding a lead to Monarch and about him doing nothing to help them. Hearing him sorrowfully admit, that he failed to watch them properly due to distractions of the modern world.
Not seeing Rena in a great while Cat Noir likely suspected she was inactive until «Strikeback» when Carapace unveiled her location. Upon seeing her new look as Rena Furtive he was aware she pulled the same costume change trick he did back in «Kuro Neko». But thanks to him switching places with Félix and Félix’s betrayal, Adrien unintentionally stripped Alya of her powers however Cat Noir still has her support despite his mistake. He comes across Alya as Scarabella in «Hack-San», at first he had a very cold relationship with her.