Berserk allows the user to declare Move + CC Attack as an Entire Order. Can I use this CC Attack to make Coup de Grâce?
Coup de Grace is not a skill on its own, it is a quality of the CC Attack skill. You not only can do a Coup de Grace when Berserking, you have to if able.
All correct, Coup de Grâce is no longer a skill, it is an effect of CC Attack, only there is no obligation at all to use Berserk for a Coup de Grâce as it (Berserk) is an «Optional» Skill
Optional label on Berserk means you are not forced to use the skill, it does not mean you are allowed to opt out of some effects of the skill that you don't like if you do choose to use it. In the case of performing a CC Attack, the unit will "automatically" pass to Dead if already Unconscious and there are no optional words in the effects that allows you to opt out of this - and why would you? There's no benefits to not taking an automatic kill on the target and if playing with legacy ITS rules or homebrew scenarios you should probably address them so they are up to date with current rules.
Yes you are right, I misunderstood you and explained myself wrong. From what you wrote, I understood that if you could use Berserk to make a Coup de Grâce, then you had to do it in a mandatory way. What I meant to say is that Berserk is what is optional, that any CC Attack would produce the Coup de Grâce effect. Thanks for letting me see it.