@SkyswimskySo several things:
1) I'm going to assume Yuno used Calamity instead of God of Death since the latter is an auto skill and your description indicated it was actually Calamity.
2) Since Yuno's Lightsaber has 'Dismember' and Calamity has 'Area Attack', she actually dealt 4x damage to the Zombies since they're Legion-type. So that means the Zombie mob has been destroyed.
3) Also, I forgot that Yuno has Defend skills on her Parts that she can use to negate Damage on any of her Parts so I've been dealing out damage willy-nilly. Sorry about that.
If you choose to use a Defend maneuver, just indicate in your next post which Parts have been saved.
Remember, you can only use a Defend maneuver once per Turn (unless indicated otherwise). That doesn't mean you can only Defend once per Turn though. If you have two Parts/Abilities that has Defend, they are both usable but only once.
4) Why is Yuno's Bone damaged?