I remember someone asking about the vacant chair in our camp and I got the answer here.

It's Leonardo after we rescued him from Tower Kashion. We have to deliver him to Lenadia castle to get a very good weapon for Vera. 

The Lord's Blade. Magic +235 (I can't remember what weapon is the best one :/)

I asked about the vacant chair in my "Loose ends" thread, so thanks for solving this mystery and making this post, cpeeta! :)

While I rescued Leonardo, I simply forgot to check the camp before delivering him to Lenadia Castle.

With this, all NPC appearances in the camp should be accounted for.