The Volunteer is a Novigrad side quest with suggested level 13.

Head to the designated map marker and you'll encounter a singing troll. The troll says that he is a member of the Redanian army.

He was ordered to guard the boats. But he needed to make fence to guard the boats, so he used boats to get wood, to make a fence to guard the boats. I think I got that right.

The troll wants some paint for a Redanian emblem. Head to the nearby city and to a Redanian merchant to get some paint. The troll now wants Geralt to paint a Redanian bird emblem. He is impressed with Geralts painting skill. He then continues to sing.