The composition is fairly well balanced, with a few problems that’s easy to fix.
The background structure right behind the sword almost is at the same level as the hilt of the sword, and you want to break them apart so they don’t form a single line visually. Make the structure higher or lower, but don’t share a line with the hilt. This helps the shapes in your composition read more clearly.
The figure’s feet are too close to the bottom border of the image, making it feel like he’s standing on the bottom border. Usually, you want to avoid pushing shapes to the very edge of the image like that–leave some breathing room for the shapes in your image.
Like you said, the figure has problems, and I recommend you use references. You can easily shoot your own references with a camera and household lamps (to get the lighting you want). A mirror or tripod will allow you to use yourself as the model, or have family/friends help you. Make sure the camera angle/focal length matches the field of view of your scene.
The tree obscures the silhouette of the figure and it would be better to separate them, so they both read more clearly.