In the 'harry can control blood fanfiction', how does Harry discover his ability to control blood?

Perhaps it is related to some old magic that he inherits. One day, when he is exploring an old, abandoned place like an ancient wizard's tower. There, he touches an old relic which activates this hidden ability. As soon as he touches it, he feels a strange connection with the shadows around him and realizes he can control them.

In some fanfictions, it could be through a moment of extreme danger or intense emotion. For example, he might be in a situation where his friends are in peril from a fire - based threat. His strong desire to protect them could trigger this hidden ability. It's like a latent power that surfaces when his will is at its strongest.

In some fanfictions, it could be during a moment of extreme danger or intense emotion. For example, he might be facing a powerful dark wizard and in a desperate attempt to defend himself, he unknowingly channels lightning. It could also be through some kind of ancient magic that he stumbles upon, perhaps while exploring a hidden part of Hogwarts. Another possibility is that it is a latent ability that is awakened by a powerful magical artifact that he comes into contact with.

Well, perhaps he first notices it during a really intense storm at Hogwarts. Maybe he's out in the courtyard and suddenly the wind starts to change direction as he gets a strange feeling inside. It could be that he was in a Quidditch match and the clouds above started to move in an odd way when he was concentrating hard on winning.

In some fanfictions, it could be through an accidental encounter. Maybe he was in a situation where metal objects started to react to him unexpectedly, like when he was near a bunch of keys and they suddenly started to move towards him. This made him realize that he had this strange new power.

Perhaps he has a strange dream where he's in a world made entirely of shadows and he can manipulate them freely. When he wakes up, he starts to experiment and finds out that he can actually do the same in the real world. He might start with small things like making the shadow of a quill move on his desk, and gradually discovers the full extent of his power.

Perhaps it's through an accidental encounter with a powerful magical plant. He tries to interact with it in a normal way but ends up influencing its growth and behavior. This unexpected event makes him aware of his unique power to control nature. For example, he might touch a withering plant and suddenly it springs back to life and starts to grow rapidly under his touch.

Maybe he discovers it during a particularly intense storm at Hogwarts. He could be in a dangerous situation, like being chased by some dark creatures, and in a moment of desperation, he unknowingly summons lightning to protect himself.

It could also be due to his own inner strength and growth as a wizard. Harry has faced so many challenges and traumas throughout his life. His experiences might have awakened a latent power within him that allows him to control dementors. His strong willpower and determination, which have been developed over years of fighting against the dark forces, could be the key factor in this newfound ability.

Maybe it has something to do with Harry's exploration of his own heritage. As he delves deeper into the history of Gryffindor and his own family's connection to the founder. He comes across an old spell or an enchanted object that, when he touches it, he feels a strange power flowing through him. This power then manifests as the ability to control the flame of Gryffindor.