The Regressed Mercenary's Machinations is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Ghislain Perdium, the Mercenary King and one of the continent's top seven, started a great war in an attempt to avenge his fallen family. His plans of revenge were going smoothly until he was slain by Idun, who he had never expected to make an appearance. Ghislain thought he died, but he woke up as a younger version of himself from before the fall of his household. With this second chance, he decided to fix all the wrong pieces of the puzzle and avoid making the same mistakes he did in his past life!