Who enters the great hall? Describe him? What is he carrying and what do you think it represents

A wondrous stranger bursts into the hall. The giant-like stranger is most remarkable because he is entirely green, but he nevertheless carries an air of handsome civility, wearing sumptuous green and gold clothes and armor. His horse is equally decked in ornate green, and the knight himself holds a branch of holly in one hand and a formidable battle-axe in the other. The Green Knight represents challenge to both bravery and the code of chivalry of the knights.