To be fair to Cubs fans, he's not human.So what?
This is the first of Harry’s friends to die in Peace Talks/BattlefieldGround.
And, now that I think of it, do Nudd's death and the attempt on Etri constitute a pattern?
The Twyleth Teg are probably Wildfae, neither Summer nor Winter nor a member of the Accords. They are hereditary enemies of the Fomor, so this was a score settling, nothing more and the head a message “see our long term enemy who has thwarted us and kept us down for centuries, that’s his head that is, so when we say we can take you all, you better believe it”