Hiraheishi wa Kako o Yumemiru Manga

A brief description of the manga Hiraheishi wa Kako o Yumemiru:

The most ordinary soldier died at the end of the war with the demons. Then he woke up as a baby in his own past. Now he will make every effort and experience to avoid the tragedies that fell to the share of his loved ones, and prepare for the invasion of demons.