Is there a problem? The problem is huge!!
Duncan stared at the old man in front of him, quickly realizing that Maurice didn't understand what the gushing flame he saw signified; this scholar wasn't aware of the Sun Shard, and he most likely mistook Nina for another "Transcendent being," like Duncan's follower or something else that came from Subspace.
Indeed, Maurice thought this way. At the sight of the spouting flames, he regarded his "student" as a being similar to Duncan. As for why these "Subspace family members" would look like a giant and the other like fire, he didn't give it much thought—strange was the norm for Subspace, after all, that place had no living people, and the big shots could look however they wanted...
However, now seeing Duncan's reaction, Maurice finally began to vaguely realize that the situation might be different from what he had guessed.