The One shirt was designed to gain domination over all the locations of Middle-earth. The Designer intended it to be the most powerful of all Shirts, able to rule and control those who wore the others.
Be aware! Wearing it might turn you into an evil spectrum, which struggles to jealously keep all locations secret, only for its own profit... for eternity.
“One Shirt to rule them all, one Shirt to find them, one Shirt to bring them all and in the darkness bind them”