Spirit Willow

The Spirit Willow is a Spirit Tree that serves as the heart and guardian of Niwen, like Nibel's own Spirit Tree. The Willow's light is Seir (a light akin to Sein, who is bound to Nibel's tree).

Before the events of Ori and the Will of the Wisps, the Spirit Willow died from old age, causing Seir to shatter into five Wisps and leaving Niwen to decay.

Appearance

The Spirit Willow was not too dissimilar to Nibel's Spirit Tree, the main differences being purely aesthetic.

1. The Core in which the Tree Spirit rests is much closer to the ground
2. There are two main trunks which split at the core
3. Though we don't see the Willow as it truly was in life, its temporarily revived ghostly form bears leaves that are appropriately more willow-like, dangling from the branches like wispy ribbons
4. The Spirit Willow seems to be shorter than the Spirit Tree

Gameplay

The Spirit Willow is seen at the beginning of the game and later found at Willow's End, Ori's objective within it being the cleansing of the Decay that befell the Willow and is currently afflicting the rest of Niwen in the absence of the Light.

Ori and the Will of the Wisps

Eventually, after Ori and Seir clear out the Decay beneath the old Willow, the make it to the top of the ridge to stand before it. It is here that Seir merges with and briefly revives the ancient tree, but it is only a ghostly specter of its former self. The Willow thanks Ori for healing what was lost. However, she says that her time is past and therefore can no longer care for the light. In order to replace her, Ori would have to embrace Seir, leave their old life behind, and become the new Spirit Tree of Niwen to save the lives of all. But just before their joining can take place, Shriek flies by, grabbing Seir to crush them in her talon before tossing them on the ground, leaving Ori to battle against her in a grueling final fight for the fate of Niwen alone.

During the battle, Shriek flies down into the unseen hollows in the earth left by the Spirit Willow's decayed roots. This causes an earthquake that rips beneath Ori as well as the rest of the Weeping Ridge which collapses, taking the remains of the Willow with it in the background. Ori continues to fight Shriek in the pouring rain, and lightning strikes fiercely all around. Finally, they defeat her, but Ori is left exhausted and barely strong enough to walk anymore, with Seir flickering weakly in the distance. As they limp towards Seir, they reflect on the happy memories they had with their family, of their deceased friend Kwolok, the Moki who helped them and of their dying sister Ku, all of who Ori may never see again.

As soon as they reach Seir, Ori takes out Kuro’s Feather - their only worldly possession - and lets it blow away in the wind. “It is time, Ori,” Seir tells them. Ori then holds them close and golden light blooms from the two to fall upon all of Niwen from atop the vacant Weeping Ridge. All of their friends, those who Ori encountered and helped along the way, bear witness to the spectacle and look on in awe. The light also reaches Ku's resting place and restores not just her life, but her deformed wing and she wakes to find Gumo and an ecstatic Naru taking Ku up in her arms for the first time since their long separation.

She, Gumo, Ku, and the Moki go to the site where Ori and Seir had merged, but all they find is a tiny patch of flowering grass on the otherwise lifeless rock. Believing Ori gone forever, they mourn the lost Spirit. Suddenly, a sprout appears in the grass as daybreak - and realization - dawn on the group; Ori has been reborn as the new Spirit Tree of Niwen. Time passes and together they help Ori’s tree grow, watering and nourishing its roots while life spreads to flourish over the former wasteland. Ori's family stays in Niwen for the rest of their days to be with them. Ku gradually grows bigger and eventually flies off once she reaches adulthood, presumably to join the rest of the owls still left in Niwen. More years pass and Ori's Spirit Tree has matured, though not yet nearly as big as the Willow nor Ori's parent tree back in Nibel. Gumo is seen helping Naru up onto the lowest of the Ori's roots to sit with them under a beautiful night sky and fall asleep in content before her image slowly fades away, suggesting that at long last she has passed from old age. Finally, the view travels up the tree's trunk to reveal the faces of Naru, Gumo, and Ku carved into it, and a single glowing leaf in Ori's branches as it detaches and floats on the wind - the first of the next generation of Guardian Spirits as decreed by the Will of the Wisps.