In a fanfiction where Black Star becomes a weapon, his design as a weapon would probably be very unique. Given his love for being flashy and his ninja - like style, he could be a weapon that has a lot of sharp edges and a sleek, black design. Maybe he'd be a sword with some sort of special ability related to his ninja skills, like being able to disappear and reappear during combat, or having the ability to cut through dimensions.
His character might become more empathetic. As a weapon, he would experience being wielded and controlled, which could make him understand Tsubaki's position better. He may develop a new sense of respect for meisters in general.
In many Black Star fanfictions, his relationship with the other characters is a key aspect. He might have interesting interactions with Maka and Soul. Maybe there's a fanfic where they team up for a special mission and Black Star has to learn to work with them in a different way than he's used to.
One idea could be that Black Star leaves to pursue a solo mission to prove his strength without relying on his friends. He might encounter a powerful and mysterious foe that challenges his very core beliefs. This would make for an exciting story as he battles not just physically but also internally.
The theme of friendship also shows up a lot. Despite his brash exterior, Black Star has friends. Fanfictions may show how his friendships are tested, for example, when he has to make a difficult choice that could potentially harm a friend, and how he navigates through that moral dilemma.
One common theme is power and growth. Black Star is often depicted as striving to become more powerful, whether it's mastering new techniques or unlocking hidden powers. Another theme is friendship. His relationships with characters like Maka, Soul, and others are explored, showing how they support and sometimes challenge him on his journey.
In Soul Eater Black Star mpreg fanfiction, a frequent theme is the relationship dynamics. For example, how his partner (if there is one in the story) reacts and supports him. Also, there could be themes related to the challenges he faces during the pregnancy, like dealing with his own strength and how it might affect the pregnancy, as well as the social and cultural implications within the Soul Eater universe.
Black Star leaving could trigger a series of events. He could end up in a place full of dark magic where he has to fight to survive. Meanwhile, back in Death City, there could be an attack by an enemy who was waiting for Black Star to be gone. The remaining characters would have to step up and defend the city without him, which could be a great source of character development.
Naruto might be a staff - type weapon. He could use it for both close - range combat and to channel his chakra or soul power. The staff could have different forms, like it could extend or transform into other shapes depending on the situation, similar to how he can transform his Rasengan.
One great fanfiction is 'The Bond Beyond Souls'. It beautifully explores the dynamic between Black Star and Kid. The author really delves into their different personalities, with Black Star's brashness and Kid's precision. It has some really cool action scenes that are true to the Soul Eater style.
In fanfiction, if Black Star turns evil, it would be a really interesting development. Black Star has always been on a path of growth and self - discovery in the original series. But if he goes to the dark side, his character arc would take a drastic turn. His pride and ambition could be twisted into something malevolent. He may start to see his friends as obstacles to his new - found evil goals. This could lead to some really intense and dramatic storylines, like battles between him and his former comrades, or him causing destruction in the name of his new evil ideology.