Non cannon lore:

W.A.R designation drones were built long before the cannon events of murder drones took place,being used for one purpose,to win a war for JCjenson.

after the war,most of the W.A.R drones that actually survived were destroyed,since they served no purpose anymore.

W.A.R designation drones were very skilled and fit for combat,which is another reason they were destroyed after the war ended,since they could be very deadly.

W.A.R Designation M-S3 would be one of the W.A.R drones to be active after the end of the war,now as a ‘retired’ war general.