My Conquest of the World through Ice Magic

My Conquest of the World through Ice Magic summary:

A [Crusade] in a world of swordsmanship and martial arts. A young man living in a remote village, Krell one day encounters a monster hidden within the depths of a cave and receives a strange book from it.
The moment he opens the book, Krell’s body is engulfed in a pale light. Suddenly, he is granted a new ability – the power of [Ice Magic]. Having obtained the legendary [Ice Magic], Krell embraces his ambitions. And thus begins the story of the youth with a unique, absolute power.