Zygarde (Z2), Pikachu and others in “Facing the Needs of the Many!”

[in it's 50% Forme, speaking telepathically] Greninja, I've come to ask a favor of you.

Pikachu

Pika? [Huh, is that...]

Serena

Was that the voice of Zygarde?

It's telepathy.

The vines that reappeared, the roots have burrowed themselves deep into the ground, and they emerge by absorbing negative energy. What we destroyed was merely on the surface. The scars from the incident that nearly destroyed the world are deep! The two of us are destroying the roots that are scattered throughout Kalos one by one.

[telepathically] However, it's difficult for even me to pinpoint their exact locations, yet, Greninja, it seems that you are somehow able to locate them.

[in its Ash-Greninja form] Ja. [Yes.]

[gasps, then remembers the negative energy from the evil roots] So that was the negative energy...!

I do not know why only you possessed that power, but I am in need of your assistance.

Will you help us with your power?

Power?

Serena

Does that mean...?

[Gasps as Ash walks up to Greninja, which is now faced with the decision of its life.]