This question involves many different factors and different novels with different backgrounds may have different answers. In some novels, there might really be a fine line between humans and demons, while in others, it might just be a fictional description used to create a terrifying or tense atmosphere.
However, in real life, it was not uncommon for a man to kill his wife and be involved in another murder case. In this case, killing a person might be a crime and the difference between killing a person and a demon might not be that big. In some cases, murder may be seen as a manifestation of a mental disorder or mental illness rather than a simple crime.
No matter what the reason was, killing was very dangerous and unacceptable. We should always try to avoid such behavior and seek professional help and treatment to ensure that we can protect ourselves and others and create a safer, harmonious and safe society.
The 'fine line' can also represent the internal struggle within the characters. Alec, being a Shadowhunter, has been taught certain values and has a set way of life. Falling in love with Magnus, a warlock, goes against some of those values. So, he might internally 'hate' the fact that he's attracted to Magnus because it challenges his beliefs. However, love is a powerful force. As he gets to know Magnus better, the love starts to overtake the initial negative feelings. In Malec fanfiction, authors often explore this tug - of - war between these two emotions in great detail.
The fine line often lies in the complexity of the characters' emotions. They might have intense feelings that can quickly shift from love to hate and vice versa.
In fanfiction, one key element is miscommunication. A simple misunderstanding can quickly shift feelings from love to hate. For example, if a character misinterprets an action of another as betrayal when it was actually a sacrifice. Another is power dynamics. When one character has too much power over another, it can create a tense situation where love and hate co - exist. If a powerful character constantly controls a weaker one's actions, the weaker one may feel both love for the protection the powerful offers and hate for the lack of freedom.
Writers can use body language. Subtle changes in a character's posture or facial expressions can show the shift between love and hate. For example, a character might have a soft look in their eyes one moment (love) and then a clenched jaw the next (hate). Another way is through dialogue. Sharp, sarcastic remarks can hint at underlying hate within a relationship that was once loving.
The ambiguity. In Malec's relationship in these fanfics, the fact that their emotions can swing so easily between love and hate creates a lot of tension. It's like a rollercoaster for the readers. One moment they're all lovey - dovey, and the next there's a huge fight or misunderstanding that makes them seem like they can't stand each other.
One common theme is the clash of different worlds. Magnus is from the world of warlocks and Alec from the Shadowhunters. Their initial interactions can be filled with mistrust and what seems like hate. But as they start to understand each other's worlds better, love begins to bloom.
One great 'A Fine Line Between Love and Hate' Malec fanfic is 'The Tension and Tenderness' on Fanfiction.net. It really delves into the complex relationship between Magnus and Alec. The author does an amazing job of showing how their feelings can shift from love to hate and back again in the blink of an eye, all while keeping their characters true to the original series.