Devils are always the wise ones who can share wealth but never share hardships.
So, when preparing various ways to escape, they absolutely won't reveal their true feelings to the other party, even if Fengo is Mack's superior and can decide Mack's future and life, it's not enough for Mack to tell him the truth.
As for Fengo, it's even more needless to mention; he's always had a strong sense of crisis.
The job of a Hell Prosecutor is essentially being a tyrant for the king, relying on oppressive rule and a mad-dog style to make all Hell Devils fear him.
He seems strong, but in reality, he can only hold his ground relying on the power and majesty of Asmodeus.
Therefore, what Fengo fears most is always the next version of himself.
Dukes like Mack are precisely the individuals he guards against.
