Item description:

Load the Chapter 9 fight and take out the ace (lancer in the far upper right corner near the objective camp). This will net you the last weapon and final decoration. All other trophies have been obtained, so it may also work for 1,000 enemies defeated (kill one enemy), all squad stories completed (finish one squad story), all missions "A" rank ("A" rank one map), etc. That hasn't been tested though.