Freeroamer
The greatest story of them all.
You were right to toss, no Ubers viable Deoxys uses Sassy. When trying to get a competitive Deoxys, you need to decide what Deoxys forme you want.Deoxys: Sassy 31/4/31/31/31/25
Between this being the first one, Synchronize failing, and those IVs, I have no idea what this is or if I should keep or not. I'm thinking I should toss it.
Edit: Tossed. This thread takes too long for responses.
If you want Deo-S, you want Timid with a 31 Speed IV at the very minimum. Good HP IVs and defensive IVs are great too, but the Speed absolutely has to be 31. Offenses aren't so important as Deo-S rarely runs offensive moves.
Deo-A will usually have Naive or Rash, mostly Naive and you should aim for the 31 IV stats to be offenses and Speed. The other IVs are largely insignificant due to its terrible bulk.
Deoxys base is unviable in Ubers, as is Deoxys-D.