Cloud is an ex-SOLDIER trying disable the Mako Reactors in Palamecia's Midgar. Obviously, a reference to the main protagonist in Final Fantasy VII.
After enter the Midgar zone, Wol is surrounded by a SOLDIER Team. Cloud comes up and intervenes.
During Wol progress, Cloud provides info about the place, explaining the urge to disable the Mako Reactors as they can kill the planet by draining the lifestream.
He keeps trying remember his past and, due the talks with Wol and Echo about the manifestation of Midgar in Palamecia and his apparent amnesia, he starts to doubt if he is really himself.
At the end of Mako Reactor 3 after Cloud departs, Echo states in her vague talk to Wol that this Cloud seems to be just a reflexion and not the original one, as something is wrong as Midgar should have disappeared with him, but there is Mako Reactor ∞ to disable yet.