... I'm actually going to count that as a good ending for the battle, honestly!
Like, there was going to be a near-guaranteed horribly heartrending tearjerker moment coming up, where Taylor and Mercy come up against the intolerable status quo invented and enforced by, among others, Mercy's mother Malice. That confrontation was never going to end in anything but Mercy having to fight her own mother, probably to the death. It probably would also have done bad things for Taylor's overall character development and journey-of-recovery; Taylor's generally both stable and world-weary enough now that it wouldn't have hit her as hard as it might otherwise, but I still absolutely can't imagine it would have been any fun at all.
Having her go out like this in a heroic sacrifice, as a clear hero, is pretty much the best way this could have ended.
Lol, nobody is going to believe Taylor controlled a Dreadgod, even if the few witnesses try to tell them that.
Most everyone was either already gone or completely out of it in one way or another, they are going to sense maybe some incredibly dangerous foreign presence but equating it to Taylor specifically is unlikely. They may think she channeled some equivalent to the Silent King that she had a link to, which is closer to the truth, but they'd just see her as a pawn. Even that's unlikely.
I dunno. It depends on whether or not Emriss really did flee when Sha Miara did, and whether Shen or Northstrider were still nearby. Even aside from that, the word of a Sage or Herald is plenty good.
Also, if anyone manages to think about it rationally, they'll find it's much less impressive than it might immediately look (though still plenty impressive). Controlling a blood shadow
is fundamentally controlling a piece of the Bleeding Phoenix, and doing that is an uncommon but not terribly rare feat in the setting. The Bleeding Phoenix is by nature vulnerable to the sort of "salami-slicing", infectious way Khepri took it over -- to having small chunks of it being sliced off, then used as power and turned against the rest to slice off a larger chunk, repeat until the whole thing is under control. That's a big part of why Khepri was able to get the Phoenix but unable to control the Silent King or the Weeping Dragon -- it's much harder to overwhelm a single monadic will at the tier of a Dreadgod than to swallow up a composite entity Dreadgod piecemeal.
Ehhh, I'm not clear it's this simple? Soul Oaths are based on understanding and agreement, not on legalistic contract words. "The lands of my mother," "the lands of my clan," "the lands of the Akura," all kind of have subtly different meanings but also have the same basic idea behind them and it shouldn't actually matter than you didn't consult your unseelie lawyer to close all the loopholes.
Of course, Monarchs are so ridiculously powerful that they have all kinds of fuckery to get around that. Presumably, the Dragon King has enough Authority and self-controlled willpower to convince his self and his soul that the oath was intended to be read hyper literally; he's also enough stronger than any remaining Akura that he could still count on a resounding victory even if a partially broken oath damaged his own spirit. I don't think this dragon attack is a plot hole of story flaw per se.
But yeah, in general terms, you can't just "well akshually" yourself out of a soul oath in this setting.
I think in this case, Seshethkunaaz can lean on the fact that he's
always fundamentally viewed nations as founded on the personal strength of their rulers. He swore an oath not to attack the nation whose right to exist was guaranteed by the strength of their Monarch; if that Monarch ceases to exist then as far as he's concerned the nation also ceases to exist, even if it later ends up being taken over and propped up by someone else.
