I'm going to say Festival of The Hunt

To cease a false war,
the bad union must be.
Struggle for a while,
till the Vacant One flees.

This maybe the heritage of that festival or Zaghnol?

The recipe for gold,
must be done without fault.
Be true with your arsenal,
or the money will moult.

Don't know, The Ogre or Synthesis Shop?

If your targeting's good,
and timing is filled.
Then your prize will be,
the decem mille.

well, maybe the rule:
Target enemy with good points
Do in times
Get the prize.

Or is it; Ragtime Mouse? (Second Choice)

To cease a false war,
the bad union must be.
Struggle for a while,
till the Vacant One flees.

Don't know about this, maybe talking about Ragtime Mouse's Life

The recipe for gold,
must be done without fault.
Be true with your arsenal,
or the money will moult.

Well, you can obtained great EXP, AP and Gil, you must do it in step, follow your heart or the money flies away.

If your targeting's good,
and timing is filled.
Then your prize will be,
the decem mille.

Target either X or O
Be in time, or he'll run away
Get the prize