Achilles or Achi as the crew would like to call him, works as a mechanic for the ship of Aurora. To some (if not all) is viewed as having a teenager-like attitude. Which at times he may not take things seriously. But when heavy situations arises he will always be there to make sure the objective is completed.
For this reason, he can also be viewed as "oni-chan" (brother) figure (to the young members of the Aurora, Junior, Enora & Gram)