How to obtain Workhorse achievement?

Question

The achievement description is “

Whether it's clearing cellars from rats or delivering quara eyes with a smile, you get the job done.” so it looks like it is also related to weekly tasks

Answer 1

You need to finish 500 Weekly Tasks to obtain the Workhorse achievement.

I've sent an e-mail to Cipsoft and they confirmed it is indeed related to Weekly Tasks.

I have 126 Weekly Tasks completed at the moment, already got Errand Runner with 100 tasks, and when I complete 500 tasks in the next months, I will update my answer with a concrete proof getting the Achievement.