Do we know for sure that Kemmler was Warden when he died? ...
We do not know for sure, but smart money says
yes: WoJ is that one huge component of the WC's anti-Kemmler campaign was to keep him the
&$@% away from the island; which sounds an awful lot like he was the Warden, and would get Wardenpower as soon as he got back there.
... Aside from necromancy was he all that bad as to warrant death without a trial? ...
I expect there was a trial; likely
in absentia, but a trial. No reason not to go through the formalities, eh? And also a huge debate, because a finding against Kemmler would amount to placing the WC into a state of war.
But... "aside from necromancy" ??!?
Seriously?Remember that it's one of just 7 death-penalty crimes the WC has.
And Kemmler wasn't just "a" necromancer -- he was the premier necromancer of the modern age, maybe even of all time; someone with the skills and powers to impress even Mab (who generally seems to regard most modern wizards (even heavyweights like McCoy & Langtry) with no more than mild interest).
And it's not like he merely animated the dead, then used them for as maids & butlers (or something equally innocuous but anime-esque amusing) -- he used them brutally to advance his personal power, an Evil Wizard in the grand traditions of Evil.
But fine. "Aside from necromancy" you say?
How about being the guy who spent over a century engineering WW1 (which arguably was in turn directly causative of WW2)? That's about 80M dead, right there. War crimes, genocide, crimes against humanity, you name it...
Even if you judge WW2 as not directly Kemmler's fault... WW2 is when he re-surfaced and "... animated mass graves and rampaged through Eastern Europe." (n.b. "rampage" is distinctly not the maids-and-butlers use of undead).
... Did he do his job on the island? Would Alfred let a warlock/criminal be Warden? Did Kemmler use the leyline for his own ends? Would Alfred allow him to do that? If he was so bad, why didn't he let some of the prisoners loose to aid him? I'm sorry but something seems a bit off here, the pieces do not fit nicely in the puzzle ...
The Warden is
supposed to use the leylines; the Warden is supposed to use all the tools at his disposal, and those are some very potent tools!
But Alfred doesn't give a f-ck about "warlock" or not, "criminal" or not... all Alfred cares about is whether the Warden is doing the job -- imprisoning the really big, really bad BigBad's, and
keeping them confined. By those standards, I expect Kemmler did an excellent job: he'd hardly want any of those BigBads running around, messing up his own plans!
We know (or strongly suspect) that the Warden can semi-release imprisoned entities, "furlough" them but keep them leashed to the island and forced to return to their confinement when the Warden says so, but (during their furlough) able to act in the world to some degree. It's apparently one of the last-ditch powers a Warden can wield, and I expect we'll see it in the BAT (likely sooner, with one or more of the lesser prisoners such as a naagloshi). So long as he put them back after, I presume Alfred was perfectly OK with any such actions Kemmler might have taken; again, it's a
feature of the Warden role, not a "bug."
[side tangent, a nasty thought: can the Warden
fully-release a prisoner? Not just a furlough, but a full-on "your time is done, the Well has no further claim upon you" ??!? AFAIK we have never seen any indication of such a thing; and
if the Warden indeed
cannot do so, then Thomas is going to be stuck with Harry as his Warden-boss even after release... likely re-pissing-off Lara, and introducing major Thomas/Harry tensions (not to mention whatever tensions will exist from the fallout of what happens with Justine/Nemesis vs Harry) ]
... Tinfoil hat time, maybe Rashid was the only wizard with enough juice to get Kemmler off the island so he could be taken. This is why Rashid limps and why the island/Alfred has a grudge against him? Because it was Rashid that deprived the island/Alfred of it's caretaker/Warden, Kemmler?
That's an interesting theory. Very interesting! I don't think it's correct, but I
do like it & AFAIK there is very little to go upon... perfect WAG material!