Delic Heiwajima

Delic Heiwajima is one of the most well known alternates of Shizuo Heiwajima's. He was created based off the cover of theDurarara!!OST, "Psychedelic Dreams". His name comes from the second half of the word psychedelic and he was created around the same time as his Izaya counterpart, Psyche.

Personality 

Delic's personality varies, depending greatly on the person interpreting him. He's most commonly portrayed as a playboy or a host type character. On rare occasions, he's depicted as a sadist or even a masochist. He is lewd, loud, and obnoxious with a love for sex. A very touchy-feely person, he can never keep his hands off his partner. That is, until the next day when they become just another one night stand.

Some people, however, design him with a much bigger heart than just a cold player, making him a caring and passionate lover to that special someone. He can even be deemed to have a dark, possessive side.

He may reflect the slightly cheeky side of Shizuo, or even go so far as to say a representation of Shizuo's violence or that side of himself that Shizuo is reluctant to let loose.  He also represents the part in Shizuo that just wants to be loved by someone. 

Characteristics

Generally, based of the original album cover, Delic is portrayed wearing a white suit with a fuchsia dress-shirt underneath accompanied by a black tie. He appears to be wearing white sneakers with pink highlights and soles. He also wears very stylized headphones attached to a very retro music playing device that appears to have a record player.

Like more of Shizuo's alter egos, Delic smokes, and the smoke usually forms into musical notes. On the other hand, Delic is more commonly depicted without sunglasses, unlike Shizuo. If and when he does have them, they are pink. His eyes are a shade of fuchsia pink, similar to Psyche's.

Relationships

Delic depicted as a knight, while Hibiya is more of a prince.

Psyche and Delic

Hibiya Orihara

Hibiya is the most popular pairing for Delic. Hibiya (whom Delic likes to refer as Chibiya) is a prince-like figure.

Most people would wonder how such a loud boastful man could fit so well with a snobby little prince. Delic finds Hibiya's spoiled nature to be very cute and he loves doting on the little prince. Plus as stubborn as he is, Delic knows he has full control 'in bed'. 

Psyche Orihara 

This pairing you would think would be the most obvious as it is known as the Psychedelic Dreams combo. Though it is not as popular as Hibiya x Delic, but it's a second closest. Lots of stories portray their relationship to be meaningful and sweet. 

Delic is normally the one to fall for Psyche. Lots of stories show Psyche as Delic's ex-lover, whom Delic mourns that he has lost, which is when Hibiya comes along later. Though, it's undecided if this pairing is a healthy relationship or not.

Another relationship that's common between the two is friends and/or bros, friendly rivalry, slight bickering, and etcetera.

Some also believe this pairing is more of family relationship, that they are often times like brothers, in a sense. Psyche is usually depicted as the naive, little kid and Delic to be the older, sex-crazed teenage boy.

Izaya Orihara 

Izaya and Delic are generally portrayed as "friends with benefits". Many fan arts depict this pairing as more hateful yet lustful. Sometimes the two are shown toying with each other's emotion.

Others believe that Delic is more virgin-like while Izaya is more dominating.

Shizuo Heiwajima

For the category of Shizuocest, this one is pretty common. Stories with Shizuo x Delic tend to make Shizuo more celibate, and Delic is helping him with experience. Shizuo is normally shown as the bottom in this pairing.  

Kanra

Basically it is very similar to the Delic x Izaya pairing, except with a lot more of a lustful aspect, since Kanra is the female equivalent to Izaya.