Saigo no Ryuukishi no Eiyuutan – Panzer Ryouheidan Senki is a Manga/Manhwa/Manhua in (English/Raw) language, GORE series, english chapters have been translated and you can read them here.
The Strauss family, a clan of warriors who fight with dragons as “Dragon Knights”. The fourth son, Solje, goes to his final battle with his old dragon Ares, to protect his family. However, due to a twist of fate, Solje is the only one who survives and vows to destroy the Faris Empire, the great nation that annihilated his homeland. He begins to fight with his new partner and comrades. They are called the “Panjal Mercenary Corps”. They are the invincible warriors led by the last dragon knight!