Fate/stay night, Ajin Recommendations
Nakano Kou from Ajin reminds me a lot of Shirou from FSN. Even though Ajin 1st season is mostly about Nagai Kei, Kou has a more significant role in the 2nd season. Kou and Shirou are both redheads with similar hairstyles; and wouldn't mind risking their own lives to save others. Luckily for them they are both near immortal (Many characters from Ajin because they are an ajin, Shirou because of some kind of plot device).
Both anime have plenty of gore and epic action scenes. A major difference is that Ajin has more realistic characters IMO, while in FSN the characters are mostly