DEMONIC FRONTLINE: THE 13TH FLYING DRAGON COMPANY

Once an embarrassment to his clan, Jin Seonu starts a new life after being sent to the frontlines, only to be killed years later by his very own brother! But what’s this? He wakes up only to find himself back where he was 10 years earlier? Armed with his knowledge of the future, he returns to the frontlines once again to prove himself for real this time!(Source: WEBTOON) — Description from AniList community (anilist.co).