Destroy, alias Deathroy, is an antagonist in Blue Dragon. He is a pet of Nene and the only remnant of the Ancients left in the present time. Deathroy repeats everything Nene says, but is capable of speaking independently. Deathroy is a background character whose details and backstory are not revealed until the very end of the game.
His english voice is Will Matthews, and his japanese voice is Yuji Ueda.
Destroy is a bio-mechanical superweapon that annihilated the Ancients' civilization long ago. It took on a much smaller form and assumed the alias "Deathroy" while biding his time with Nene to regain his old strength, but was destroyed by Shu and his party. However, he is later revealed to be one of many mass produced creatures, sometime during the Atomic Cube Crisis.
Destroy might have been intended as an homage to Daimao Piccolo in Dragon Ball, at least design-wise, since both were designed by Akira Toriyama.