Mettaton

Mettaton is quite possibly the greatest monster-made killing machine to have ever existed. Built By Alphys to be the perfect hunting machine, and containing a soul, Mettaton has become infamous due to their hunting tactics and eerie appearance by both civilians and blood thirsty monsters alike. Unlike the classic Undertale Mettaton, Mettaton is perpetually in their Neo form, after Alphys completed the construction of a more efficient energy system for them.

Appearance
Mettaton shares some similarities with classic Mettatons EX and Neo forms. They are bipedal and humanoid in appearance, however, unlike Undertale Mettaton they have a large sphere-shaped head reminiscent of a diving suit helmet, as opposed to a humanoid face. They wear deep magenta high heels, and their legs and arms are now reinforced with a crude, metal splint-like structure. Their torso is near identical to the torso of Mettaton Neo, although more refined and structurally supported to endure more damage. They also have a pair of "Wings" which are retractable, and capable of providing much higher flight capabilities than that of Mettaton Neo. Mettaton is armed with a piston-driven blade on their left arm, which when the piston driver is engaged, has the capability to almost instantly kill most monster types, however, this weapon is incredibly volatile, and could egregiously harm Mettaton during use. Because of this, it is to be only used as a last resort. Mettaton also weilds a destabilisation laser, designed to knock out monsters, or if needs be, dissect them with elegant prescision.

Personality
Gone are Mettatons dreams of being an Underground celebrity. After witnessing the horrors that unfolded when the beastly scourge spread, they dedicated themselves to protecting the innocents of the Underground, much like Undyne before them, until her unfortunate descent into beasthood. On the surface, Mettaton is very staunch and apathetic, wanting to perform their jobs with prescision and without the interference of persoal emotions, however, deep down, they are still the same old Mettaton, spontanious and entheusiastic, and yearning for a better tomorrow for monsterkind.