One interesting mha reacts fanfic could be where the characters react to seeing their future selves. It adds an element of mystery and self - discovery. For example, Midoriya seeing himself as a fully - fledged hero might make him realize how far he has come and what he still needs to achieve.
First, know the characters well. Understand their personalities, motives, and backstories. This will make their reactions more believable. For example, if you're writing about Todoroki reacting to something, you need to consider his complex family situation and how it shapes his views.
One popular 'Overwatch Reacts' fanfiction could be the ones where the Overwatch characters react to different timelines or alternate universes. For example, they might react to a world where the Omnic Crisis was never resolved. Another could be their reactions to new heroes joining the team. It's all about exploring the characters' personalities through these reaction scenarios.
The JoJo manga is mainly in black and white. Colored versions exist but are not the norm. Sometimes, colored illustrations are done for promotional purposes or by fans.
I think it's great. The characters are memorable, the plot is full of twists and turns, and the battles are epic. It's a manga that stands out from the crowd.