Create an image of a knight personifying the Earth element, clad in armor made of black marble. The knight kneels on one knee, grasping the handle of a massive greatsword with both hands, the pommel of the sword resting against their shoulder. The black marble armor is intricately designed with natural patterns, such as veins of darker minerals, embedded gemstones, and textures reminiscent of rocks and mountains. The armor has a rugged, ancient look, with some parts covered in moss and small vines to symbolize the knight's deep connection to the Earth. Through the helmet, the knight's eyes glow with an eerie green intensity. The greatsword's black marble hilt and dull, earthy blade blend seamlessly into the knight's armor, exuding an aura of ancient power and unyielding strength.