Mesec is a human-bird hybrid created through the effects of the C-Virus. Its name is derived from the Serbian word, mȅsēc (ме̏се̄ц), which means "moon".
Like many other human mutants, Mesec were byproducts of Dr. Carla Radames' C-Virus research, which sought to turn humans into B.O.W.s rather than through the traditional cloning methods. A number of experimental viral strains were created to splice the DNA of select animals into human test subjects' genomes. When the strain that turned humans into Mesec proved useful as a bioweapon, it was mass-produced and distributed to the Edonian Liberation Army.