Edna had lost interest in how Anmur constantly seemed to court death, but she had a feeling that the Undead Tribe, or rather the William behind them, was very interested in these things.
William is indeed a righteous deity, but he's hardly so friendly towards the Black Dragon Brothers of Toril... innate evil is sometimes actually a very useful trait.
Even the so-called benevolent Midnight would at most drive away these Black Dragon Brothers, not kill them.
Even Tyr might be slightly better than Midnight, but not by much.
Even the Black Dragons themselves had little room to struggle, given that they're part of the Evil Faction and lack the strength to resist.
So Edna wasn't surprised at the choices made by the Black Dragon Brothers, only finding them to be exceptionally shrewd dragons.
Her Elvia probably couldn't make such decisive decisions... there were so many benefits that even clouded the eyes of the White Dragon Queen.
