'Has he noticed?'
Satoras mentioned in the Netherly Swathe that even those "old monsters" would have difficulty discovering his true identity. For him to refer to them as old monsters, Satoras definitely meant those at the peak of the legendary realm.
Izroth knew that Solomon was strong, but he did not believe the General's strength had yet reached the peak of the legendary realm. However, Izroth was aware that Solomon possessed a skill that allowed him to see things that were otherwise hidden and connect any missing pieces in between—Absolute Symmetry. This was one of the reasons why Aurie suggested informing the General of Satoras' real identity. With his Absolute Symmetry, he would immediately notice that something was off with Satoras and that he was somehow connected to Izroth.
'What a useful skill. Well, it's not as though I planned on hiding it.'