Sorry, I didn't explained it well.


So they are not page numbers( well, they were before I converted the file from .epub to .doc ).

Example of the second case:

After a shocked pause for a couple of years, one of the
12
clump said: ‘He just went! Just like that! One day he was here, next he was gone!’ If the other trees had been humans, they would have shuffled their feet.

What I want is to delete all numbers in such case ^ (numbers that are a paragraph on their own, not within a a paragraph with text) , and unite the upper and lower paragraph IF the lower paragraph starts with low cap.

Try using the following wildcard Find/Replace:
Find:
([!0-9]{1,3})^13[0-9]{1,3}^13
Replace:
\1^32