One reason could be a hidden disease or affliction that is unique to the fanfiction world he is in. It could be something that has been passed down in his family magically. Or perhaps he has been in a situation where he was exposed to a harmful magical energy source for too long. This continuous exposure could gradually damage his body and result in coughing up blood. For instance, if he was trapped near a leaking magical artifact that emits harmful rays.
Well, in some fanfictions, it might be related to his demigod powers. Since he has a connection to the water element, blood being a liquid could potentially be manipulated in a way similar to how he controls water. Maybe he can sense the water content in blood and use his will to move or influence it.
Some fanfictions might suggest that Percy's control over blood is a new power he discovers while on a special quest. He might find out that his powers are not just limited to water bodies but can also extend to the fluids within living beings. He could start to experiment with this new - found ability, and at first, it might be a bit clumsy. But as he gets more practice, he could use it for various things, like healing (by manipulating the blood's flow to injured areas) or even in combat (by making an opponent's blood act in a way that disables them, like making it rush to their head and cause dizziness).
One implication could be in the area of healing. If Percy can control blood, he could potentially direct it to areas of the body that need repair. For example, if someone has a cut, he could make the blood clot faster by controlling its flow and the platelets within it. This would make him a very valuable asset in any medical emergency within the world of the fanfiction.
One implication could be in combat. He could potentially use the blood of his enemies against them. For example, if an opponent is bleeding, he could make the blood blind them or make their movements sluggish by interfering with the normal blood flow.
Perhaps he has been exposed to some sort of deadly and unknown substance in the mythical world. This could be a new type of monster venom or a strange plant that he accidentally ingested. The substance could be attacking his body from the inside, causing his internal organs to bleed, and thus he throws up blood.
Well, a major theme is the adaptation to new environments. When characters from Percy Jackson enter the True Blood world or vice versa, they have to adapt to the new rules, cultures and threats. There's also the theme of loyalty. Characters may have to choose between their loyalty to their original group (like the demigods in Percy Jackson) and their newfound allies in the True Blood world. This creates a lot of internal conflict and interesting storylines as they struggle to make the right decisions.
Well, in the world of fanfiction, anything can happen. Regarding Percy Jackson dying in Blood of Olympus fanfiction, there are many fanfictions out there with all kinds of scenarios. Some writers might kill off Percy to explore themes like sacrifice, the impact on other characters, or to create a really dark and dramatic storyline. However, the original series doesn't have this happen, so it's all about the creativity of the fanfic authors.
In Percy Jackson fanfiction, families can be depicted in various ways. Some might show Percy's family having new and unexpected adventures together. For example, his mom could discover a new magical ability that she uses to protect the family from an ancient threat. Another idea could be that Percy's half - brother Tyson becomes a key figure in protecting the family from monsters that target them specifically because of Percy's fame among the demigods.
One idea for a Percy Jackson famous singer fanfiction could be that a famous singer is actually a demigod in disguise. Maybe they use their music as a form of magic or to communicate with other demigods secretly. For example, their lyrics could hold hidden messages about upcoming quests or threats to the demigod community.