User blog comment:Metadwarfosis/In anticipation of volume 11- Dwarven Kingdom and Expectations/@comment-29037426-20160801012958/@comment-29248623-20160801153834

Just checked that out and there was no mention of them (the S.T.) killing the CDL. The only mention of cases of dragon-slaying was the worker Parpatra of Green Leaf, and the 8 Greed Kings.

There's also that bit about 3-4th tier magic casters using carpet bombing to kill dragons but that was just a suggested tactic.