The story told by Angel was entirely a reconstruction of a relatively reasonable logical chain, based on known results and reverse engineering. If one really wants to pick out flaws, there must be some, because human thinking is multi-threaded, and finding order out of chaos promptly is relatively difficult.
However, if we don't consider these deeper issues and solely look at it from both surface and deeper layers, Angel's inference can be valid.
Moreover, the final effect was better than Angel imagined.
Cicia not only believed Angel but also filled in some gaps herself, revealing the secret story between Margaret and the Wise Sovereign back then... And Cicia's assumptions are very likely true.
This actually corroborates Angel's suspicion, the Wise Sovereign certainly knew about Margaret and Augustine's story, and it even might have pushed for them to meet secretly.
Even Dororo's inspiration—"The Sage is not foolish"—points towards this Sage.
