The four men were covered in black equipment from head to toe. Black hats, black coats, black shoes, and even black gloves on their hands.

Moreover, their black outfits were very different from any ordinary black fabric. Most black fabrics were just black in color, but the color of the material of their accessories was very thorough, like a black hole.

In truth, the reason for such an effect was that a layer of ultra-black material with a very low light refractive index was attached to the out