Shokei Sareta Saikyou no Gunnyou Majutsushi, Haisenkoku no Elf Hime to Kokka Saikensu ~ Sokoku yo Jama Suru no wa Kattedaga, Sono Majutsu Tsukutta no Ore na Node Kikanai ga? ~ 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

The magical nation of Ingressa came to dominate neighboring countries with the power of groundbreaking military magic. Supporting this dominance from behind the scenes was Hert Eisenheim, who rose to the rank of archmage at a young age. However, due to a scheme by the court magician who was jealous of his talent, Hert was executed as a war criminal – but when he woke up, he found himself summoned before a young girl. The girl’s name was Iris Refrain, and she was the first princess of the elven kingdom that he had destroyed. This is the start of a rebellion fantasy story about a banished man and a destroyed girl rebuilding a nation!