Manga that involves a boy with cursed mechanical dragon wings whenever he is in danger I cannot find the name of the manga.


The boy ends up joining a mercenary group that has a talking Alligator as the leader.
He teams up with a vampire girl, a robot dude with his robot dogs.
In the last chapter I read, his team was stopping a slave trafficking caravan.
This is definitely Stealth Symphony


Boy with cursed mechanical dragon wings: check, the protagonist
joining a mercenary group with a talking alligator boss: check
Vampire Girl: check
Robot dude with robot dogs: Check, no link found :(
Stopping a slave-trafficking caravan: Check, that's about chapter 6 - 9




Synopsis from MAL (taken from MangaHelpers):


  In a world where elves, dwarves, and invisible dragons live in harmony
  inside a metropolitan city, Jig sets out to find someone or something
  that can unleash the curse that he carries on his back. As he attempts
  to survive in the city of Jinbocho, a city filled with fantastic
  secrets and organizations, he encounters many powerful individuals who
  set out to either destroy him or save him. Will Jig be able to
  discover the true secret of his curse, or will it lead him to his own
  demise?