Ayato was the first person Yui met when she moved into the Sakamaki Mansion and was about to drink her blood if not for Reiji's interference. However Ayato is the first one to drink her blood and comments that its "the best" blood he's ever had.
If Ayato is chosen in the games, he and Yui will begin a romantic relationship, their happy ending depends on how many points the player gets. Ayato get's angry when he see's any of his brothers with Yui, as when he found out that when Shu drank her blood, he immediately confronted him and told Shu not to touch her.
In the first season of the anime Ayato is seen as the main vampire, as he has most scenes with Yui and comes to care for her faster then his brothers. In the second season, Ruki Mukami is the main vampire from his family and has a rivalry with Ayato over Yui.
AyaYui is a popular ship in the Diabolik Lover's fandom. This is mainly due to the anime where the two's relationship is the main focus, it is also supported as Ayato has married Yui in all of the Diabolik Lovers games, unlike the other characters.
The paring is popular as Ayato, who is a cruel and sadistic vampire, actually has a soft side that only Yui see's, despite saying he doesn't care for her, he does and will chase after her if she is being hunted down by other people that want her.
It is a very common fan fiction trope that Ayato is a tsundere and, despite him saying how much Yui belongs to him and is only his, has quite a hard time coming to realise his romantic feelings towards Yui and declaring he loves her.
- Ayato was the first person Yui met in the series and was the first vampire to suck her blood.
- Ayato is mainly used for official art. In CD VS he is always the one to hold Yui.
- When Yui first met Ayato she thought he was handsome.
- He is the only one to marry Yui in all of the games.
- He is the main vampire in Season One, it focus a lot on his relationship with Yui then his brothers. In the Second Season Ruki is the main vampire from the opposing family who begins a rivalry with Ayato for Yui.