Well, in general, Shizuo is often depicted as the strong and hot - tempered one. In fanfiction, he might be shown as being very protective or possessive in a relationship with Izaya. Izaya, on the other hand, is usually the sly and manipulative character. In such fanfictions, he may use his wits to either get closer to Shizuo or drive him crazy. But remember, lemon fanfiction often has inappropriate content, so this is just a general view of how they are typically characterized in more appropriate fanfictions about them.
Celty might also interact with him. She's often involved in the events of the series. A drunk Izaya could be a source of confusion for her, or perhaps she would try to help him in some way, seeing as she has a kind heart despite her rather spooky appearance. Another possible character is Namie. Since she has a complex relationship with Izaya, she might be the one to find him drunk and have to deal with the consequences, whether it's covering for him or using his drunken state to her advantage.
Izaya might first use his wits to quickly assess the differences in the new time period. He would likely start by observing the people and their behaviors. If it's a time before the gangs in Ikebukuro were so prominent, he might be initially confused but then start to see the potential for new kinds of manipulation.
Another theme is the exploration of Izaya's new identity. As a girl, she may face different challenges and opportunities. Fanfictions often explore how she copes with this new gender identity in the world she exists in. For example, she might use her femininity in different ways to achieve her goals compared to when she was male. This can add a whole new layer of complexity to her character.
One popular izaya light novel is 'Durarara!!' It has a complex and engaging story with a diverse cast of characters. The setting in Ikebukuro, Tokyo, adds to the unique atmosphere. The characters' interactions and the various sub - plots keep readers hooked.
Many female Izaya fanfictions have the theme of redemption. They might show Izaya as a character who is capable of change through his interactions with female characters. Or it could be the other way around, where the female characters are the ones in need of redemption and Izaya plays a role in that process. There's also the theme of the 'outsider' as Izaya often seems to be an outsider in the Durarara!! world, and female characters may share or oppose this aspect of him.
One possible plotline could be that Harry somehow gets transported to the world where Izaya exists and they form an unlikely alliance. Maybe they team up to solve a mystery that is plaguing both their worlds.
I'm not sure specifically as there might not be a widely known 'erad izaya light novel' in general knowledge. It could be a very niche or self - published work.
One way is to have a situation where they are both physically and emotionally exhausted. For example, after a big battle or a long - running chase. In that state, they might unconsciously seek comfort from each other and end up cuddling.