In novels set in Europe, you might come across very long aristocratic names. This is common even in fantasy fiction from other worlds, a prime example being 'Louise Françoise le Blanc de la Vallière' from 'The Familiar of Zero'.

Japanese names may seem short, but there once existed a complex naming system. This system evolved to become even more intricate over time. For example, the official name of the famous 16th-century feudal lord, NOBUNAGA Oda, was 'Taira no Ason Oda Kazusa-no-suke Saburou Nobunaga'. 'Taira' represents the clan name, 'Ason' (or 'Asomi') is the noble title, 'Oda' is the family name, 'Kazusa-no-suke' is a type of position, 'Saburou' is a social name, and 'Nobunaga' is the true name, only to be used by his family.

During the modernization policies in the late 19th century, this complex naming convention was simplified, and people were left with just a family name and a given name.

Reference

https://ja.wikipedia.org/wiki/氏姓制度

https://en.wikipedia.org/wiki/Uji_(clan)

https://en.wikipedia.org/wiki/Kabane

https://thefamiliarofzero.fandom.com/wiki/Louise_de_la_Vallière

https://www.bushoolife.com/name/

Source: https://www.reddit.com/r/touhou/comments/14uuu2b/comment/jr9dqz4/