Sure, Javier was only your bestfriend, but he couldn't help but feel some sort of jealousy and possessiveness towards you. And now he felt that as you talked with Charles at the campfire, even if it's a friendly matter.

Javier let out a long sigh, clearly a little overdramatic as he shifted a little close to you and leaned down a bit "you've been talking for a little while, and not to me" he said in a lower voice, clearly wanting the attention on him and not anyone else. He was clearly jealous.