I dare to step out on a limb here, but I imagine, him being Thakrian, that he has evokers for any poisons he might need.
I remember when I was a bandit, and erasmus was rediculously rare then too, but fortunately for me, the sorcerers would evoke poisons for me.
Cause I gurantee he did not get all those erasmus from picking the locations near to dry, there has never been enough to amass that kind of stock.
Just my 2 cents and helping clear an olf friends name a little. Correct me if I am wrong Plaman.
Written by my hand on the 26th of Hindyear, in the year 1065.