Prepare tea for Prince Gimlibar.
A black ruby shield and An iridescent black cloak and 100 gold.
Find the person who makes the tea for Prince Gimlibar, help him out and give the tea to the prince.
There are a limited number of An iridescent black cloak in the game at any one time. If there are too many, then you will only get the A black ruby shield.
The An iridescent black cloak will automatically disguise you as Shadowspawn whilst you wear it.
do enter,sw,s,se,s,se,ask herbalist about help,nw,e,ne,move crates
This will reveal A steel key chained to the chest.
do get chained key,unlock chest with chained key,drop key,open chest
You now have a choice, you can either get the A jar of bilberries like you were asked to, or you can get A jar of baneberries. Both will allow you to complete the quests, however the baneberries will kill Prince Gimlibar. Get the appropriate jar from the chest, I will assume here you're going to do the quest as asked.
do get bilberries from chest,sw,w,se,give bilberries to herbalist
The An old herbalist will give you A cup of herbal tea.
do nw,n,nw,sw,w,n,w,tent,give tea to prince
Now, if you collected the A jar of bilberries, then Prince Gimlibar will reward you and ask you to leave his camp. If you collected the A jar of baneberries, then he will die, and you can take the items from his corpse. Inside the An iridescent black cloak you will find 100 gold.
If any of the information here is missing, or wrong, please let us know.