Yveltal is a legendary Pokemon in Kalos with the power to take life which is said to appear every 1000 years. On the day that Prof. Sycamore's package arrived in Vaniville Town, it appeared alongside its counterpart, Xerneas, and the two wrecked havoc as they clash against each other. Afterwards, it turned into its dormant Cocoon Forme. Later, it was discovered by Malva and ended up in her hands. At the end of its battle with Xerneas, it reverted back to its dormant Cocoon Forme.