One common way could be through using his magic in a subtle way. For example, he might use magic to create situations where Alec has no choice but to follow his lead. Maybe he makes it seem like the only option for Alec to protect his friends or family is to do what Magnus wants.
One characteristic is the focus on the relationship between Alec and Magnus. It could be their romantic relationship, like in many fanfics where their love story is explored in great detail. Another is the exploration of their individual personalities. For instance, Alec's loyalty and Magnus's magic are often highlighted.
Love is a very common theme. Their relationship, which is between a Shadowhunter and a warlock, is full of challenges and the fanfics often explore how they overcome these through love. Another theme is acceptance. Alec has to accept Magnus's different lifestyle as a warlock, and Magnus has to accept Alec's duties as a Shadowhunter.
He may also try to reason with Magnus or the kidnappers. Alec is a smart guy, so he might try to find a way to get out of the situation through dialogue. He could point out the negative impacts of their actions on everyone involved.
Through the adoption, they might face external challenges like discrimination from certain parts of the Shadowhunter world. This would make them rely on each other more. They could have late - night talks about how to protect the child and in the process, they would share their fears and hopes for the future. This would strengthen their emotional connection and make their relationship more mature. Also, seeing each other as parents could add a new layer of respect and admiration for one another.
Love and acceptance are big themes. In many fanfics, Alec has to come to terms with his feelings for Magnus, a warlock, which goes against what he has been taught as a Shadowhunter. Also, there is the theme of sacrifice. Sometimes one of them has to sacrifice something for the other's safety or well - being, which really shows the depth of their love.
There are several fanfics worth checking out. For example, 'A New Beginning for Alec and Magnus' which is about them starting a new chapter in their lives. In this fanfic, they face new challenges and grow even closer as a result. Some fanfics also explore their powers in unique ways, like 'Alec and Magnus: Powers United' which shows how their combined powers can be used to save their world from a great threat.
One common theme is love and relationship development. It shows how Magnus and Alec's relationship grows and overcomes various obstacles. Another theme could be adventure, where they go on quests together while being in a relationship.
Jealousy can also be a common element. In these fanfics, there might be instances where Alec is jealous of Magnus's past relationships or his popularity in the Downworld. Magnus, on the other hand, could be jealous of Alec's closeness to his Shadowhunter friends or family. Another aspect is fear of abandonment. Given their different natures and the challenges they face in their relationship, both characters may fear that the other will leave at some point.
One popular theme is the first kiss. Writers often explore the nervousness and anticipation of Alec and Magnus before their first kiss. It could be set in a romantic location like on a rooftop under the stars.