While watching episode 114 (Erza vs Azuma) I noticed a little green (pig samurai?) guy in the background. Any idea who or what this is?
The person (Well technically not people) you spotted are called "easter eggs".
Src from here: fairytail.answers.wikia.com
In every episode, at least once, a little creature is placed somewhere.... These creatures are known as "easter eggs", as they appear in the anime but serve no purpose. They are not part of the plot, nor an important factor in the anime.....
Here is a YouTube video of all the easter eggs that appear in fairy tail. If you want to see the scene that you referred to, just skip to 3:26.
Different types that appear (Sometimes multiple times are)
- Green one's with a white square with arms and legs
- An Exceed
- A little pink mouse
And some others too like these:
Oh yeah, and look, I found the green "easter egg" from the photo you provided too. ^^