I just got this achievement:
10:13 Congratulations! You earned the achievement “Errand Runner”.
Unfortunately, I couldn’t take a good automatic screenshot because it happened right after I selected the new Weekly Tasks for this week.
So far, I have 82 completed Weekly Task points, and during the last two weeks I completed all creatures and all delivery tasks without missing any.
I also have the task slots unlocked, for a total of 9 kill tasks and 9 delivery tasks.
According to Tibia Wiki, the achievement description is:
“Your stash is cleared, your bestiary completed but the grind has only just begun.”
Source: https://tibia.fandom.com/wiki/Errand_Runner
Hopefully this information helps. Have a nice day
PS: I was actually about to ask the same question, since I was also confused about how I got the achievement. This question came up while I was searching, so I thought it would be more useful to share my experience here instead of opening a new one!
