Duplighost

Duplighosts are ghost-like shapeshifters that can take on the appearance, voice and abilities of other people. They first appeared in Paper Mario, and a single Duplighost named Doopliss was later featured in the sequel, Paper Mario: The Thousand-Year Door. Duplighosts are set to make their Super Mario Bros. X debut in Alternate Kingdom, where the species is set to have a species leader like Goomboss and Petey Piranha. They also live on the Eleanor Kingdom, in which most folks rumored them to be mostly living underground with their ancestors. Some from the Blaize Army serve as Blaize's top spies, tricking Mario for someone else and steal anyone's identity.

Background
A long time ago, there existed high-ranked shapeshifters in ancient times. Before they disappear from the world, they are reborn as Duplighosts, except that one of them still exist.

Alternate Kingdom
Duplighosts are set to appear in Alternate Kingdom. It is currently unknown where the Duplighost might appear for the first time, however, it's confirmed Duplighosts will appear in Venom Woods.

Trivia

 * The name is a pun off of the words "duplicate," which means to make copies of, and "ghost."