The D-class soldiers are upgraded versions of their predecessor, the F-class. However, this does not stop them from being cannon fodder, but they have the right to command the lower class, but their defense leaves much to be desired.
Pros:
+ Slightly more extended issued arsenal of equipment
+ Availability of necessary protective equipment
+ Ability to command F class
+ Adamant obedience to higher classes and even mere units
+ The presence of regeneration
Minuses:
- Not a very good defense
- Practical complete lack of tactical thinking
- Clumsiness in close combat