Another World Dragon Shadow Roaring to the Sky

[The mercenary king travels through another world + practices martial arts, resists foreign enemies, rectifies government affairs + gets promoted step by step + sees the beauty of spring + fights between humans, immortals and demons] The mercenary king traveled to a different world and was reborn as a member of a special organization. When investigating mysterious cases, he suddenly discovered that mutated creatures, immortals from heaven, and demons from hell have all appeared in the world! Wow, this world is so amazing, isn't it? By chance, he began to practice martial arts diligently, and was ordered to expedition to Goryeo to resist the invasion of the Japanese island country. He fought passionately and made many meritorious deeds; after his triumphant return, he rescued Zhongliang, faced off against the traitors, and rectified the government. A heavenly fairy, a naughty girl, a confidante, a cold princess, a charming witch... The flowers are blooming, it's so beautiful! But why did I get involved in this war between humans, immortals, and demons? The only way you can find the answer is by yourself!