I don't know; I haven't read this novel.
Ah, ok. One point worth noting is that Ascher isn't actually *immune* to fire/heat; she does get burned by contact with the lever in the Gate of Fire.
In DFRPG terms, I'd give her Mythic Toughness against fire (combined with using an evocation shield) but not actual Immunity to it.
I'm not sure why that is except to encourage players to evolve into wizards, to seek "promotion" in order to become more powerful.
Because at the time DFRPG was published, it seemed pretty clear that that's how Dresdenverse magic worked... really powerful practitioners all had broad-spectrum ability.
From GS and SG it's possible Harry was wrong about that; although I'm not entirely sure, given that Mort being better than Harry at his field doesn't mean he'd be better than a wizard that actually put time and effort into that field (which Harry mostly hasn't done), and given that
Ascher was actually a Denarian so isn't indicative of what "Focused Practitioners" can actually do.
The problem is: That is something the rules can't really offer: High control is usually not that interesting.
If you have just two points of power (as in conviction + boni) and 8 control (discipline+boni) - what is there you can do, a Caster with power 5 and control 5 can't?
Well, you would hit more often with evocation attacks, but do far less damage...
But that's actually kind of my point. I don't think Ascher is actually
more capable than Harry, even in her field. She does her stuff
differently, but I'm not sure she can accomplish goals he can't.
Harry never had to really think about getting through the Gate of Fire, since Ascher did it immediately after Harry found out it existed. That doesn't mean he couldn't have found a way - some of the Winter Ice and fire/ice stuff he's done is
really impressive, for example.