The Golden Roc was a Demon Emperor-level expert. In Purgatory, it was considered one of the fastest flying demons.
'Why has it been left behind in such a place?' Azaroth found it weird that this Golden Roc's descendant was in this demon nest.
If it was him, he would assign such a valuable subordinate to a better location.
'Perhaps his bloodline isn't known to them. In fact, this guy himself doesn't appear to be aware of his Bloodline Ability. My Bloodline Pressure is forcefully activating his Bloodline Ability, though.'
'For him to have become a Demon Lord without even activating his Bloodline Ability. Impressive.'
Azaroth was impressed because a demon had to forge his path over corpses to become a Demon Lord or a stronger being.
Without activating his Bloodline, a demon would have rather limited strength. At least, he could only be considered among the average demons.