You can start by looking on fanfiction.net. It has a large collection of fan - created stories, and there are likely to be quite a few Alec Seregil fanfics there.
One great Alec Seregil fanfic could be 'The Adventures of Alec and Seregil'. It delves deeper into their relationship and the adventures they might have beyond the original story. Another could be 'Alec's Growth' which focuses on Alec's character development within the world they inhabit.
Alec is likely a character in the fanfic, perhaps someone who is vulnerable to manipulation. Magus is the one who does the manipulating. Without more context from the fanfic, it's hard to say more about their specific identities or backstories.
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.
One great Alec Lightwood fanfic is 'The Light in Alec'. It beautifully explores Alec's character growth. Another good one is 'Alec's Journey' which focuses on his relationships within the Shadowhunter world. And 'Alec's New Path' is also a popular fanfic that shows Alec in different and exciting scenarios.
I'm not entirely sure specifically what that particular 'alec mpreg fanfic' is about without more context. 'Mpreg' stands for male pregnancy, which is a common theme in some fan - created fictional works. It could be about a character named Alec experiencing a male pregnancy within the universe of a particular fandom.
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.
Well, 'alec tortured fanfic' might be a work of fan - created literature. Maybe it's part of a particular fandom where Alec is a character who endures torture. It could be exploring themes like pain, survival, or the character's development in the face of such extreme circumstances. However, without reading it, it's hard to say exactly what it entails.
A lot of Alec Winchester fanfic will have elements of adventure. Since he's a character who is often in the thick of things, the stories might take him on quests or dangerous missions. They also tend to expand on his backstory, like where he came from and what made him who he is. For example, some fanfics might explore his family history and how that influenced his present actions.
One idea for an Alec Lightwood birthday fanfic could be to focus on a surprise party his friends throw for him. They could transform the Institute into a magical wonderland with enchanted lights and floating decorations. Magnus could use his magic to create a unique gift, like a constellation of Alec's favorite stars that can be seen from inside the Institute. His sister Izzy might make his favorite meal, and Jace could present him with a new weapon he's been longing for.