Fairly short but intriguing, the setup had the right amount of mystery. The dead boar, its wounds, the mysterious fluid, the patch of cloth. It's a lot of things that don't add up, and it creates tension so that we, the readers, are already dreading what that velen is going to do when he shows up.
I did not expect Caniir to be so grievously wounded so early in Kai's story. However, it speaks to good writing that Kai, still being relatively green, fails to react in time even though his instincts had him on edge. Great start to this little arc.