What is the purpose of Klein wearing a monocle in his left eye?

Hide your identity. Klein's full name is Klein Moreti, and he is the protagonist in The Master of Secrets written by squid, an online writer who loves diving. He has multiple identities, wearing a monocle on his left eye to hide his identity in the status of Paro, a German, and wearing a classical hat in the status of Merlin Hermes. The novel was first published in Reading, and was selected into the list of China's online literature influence: 202 1.