"Something came from above. It changed those it touched." Spiderling
The Decay originates from dying Spirit Trees that have lost their light and it spreads as soon as the light of those trees fade. It is similar to a plague, infecting lightless beings in the vicinity of decayed areas. It saps their life and energy, leaving them to become skeletons or stone statues, this effect being mostly visible in Ori and the Will of the Wisps. Any essence of Decay, such as a tree branch from the Silent Woods, can infect others and cause its surroundings to wither and die.
Effects on Nibel[edit | edit source]
The balance of Nibel's three elements is destroyed after Kuro removes Sein from the Spirit Tree.
With the decay now nesting in the remains of the element's origins, Ori has to free all elements of Nibel to restore their balance, so the light may keep them in control after. In the beginning of Ori and the Blind Forest , the decay can be seen causing massive crop failure, demonstrated by the fruit trees that nourished Ori and Naru no longer growing viable fruit.
Effects on Niwen[edit | edit source]
The Decay initially spreads from the Spirit Willow through Niwen after Seir shattered, consuming almost all of Niwen.
The Silent Woods serve as the most decayed area of Niwen and display the most deadly effect the Decay has on the ancient forest, other areas within Niwen has displayed different ways the Decay affects the Forest.
- Mouldwood Depths - Because of the Decay, the darkness within the spider den has become lethal to anyone unfortunate enough to be engulfed in it.
- Baur's Reach - After the Decay arrived, an endless winter replaced spring.
- The Wellspring - A Stink Spirit settled in the Wellspring, causing water to become foul and impassable.