u/H2SO4-1191

Went to Arnskrone Castle ruins east of Velen and found an ancient leshen, it was a boss fight cause' there was a health bar, I dropped its health to less than 5% then it sent wolves and disappeared, so I was wondering whether I messed up and couldn't kill it or it's just designed this way for a second encounter later.

By the way it's my first time playing the Witcher 3 after beating 1 & 2 so I don't know about this and I couldn't find something about leshens escaping by googling.