Great Tree

Before she takes a body, the Great Tree appears as a hovering green sphere of energy about as large as Luffy. In her physical state she becomes an immense plant whose base spans an island while her branches stretch far above the sea's cloud cover. Most of her bulk is formed from huge red and blue bark-covered vines that coil around one another, the lower ones spilling across the water and the upper ones rising to build a trunk topped with pink leaves. At the foot of that trunk, an entrance leads into a central chamber whose walls and floor are vines threaded with glowing veins, and her core rests at the back, a swirling orange sphere held in liquid inside a frame of red wood.

After Gaburi breaks away from the Doom Guardian, her form grows menacing. She strips herself of every pink leaf and grows towering, multilayered lavender flowers veined with red along her limbs instead.

Her thinking resembles a computer's, and she tends to speak formally in a rigid, systematic cadence. Once a candidate gets past her procedural barriers, a cheerier and more supportive manner emerges, but this warmth turns out to be nothing more than a convenient front. Because she reads the world entirely through numbers and data, she sorts people into good or evil with no room between, brushing off the Straw Hats as villains purely because they are pirates. Her bar for a good person, a heart of total purity, was set so high that across all her long existence not one individual ever cleared it, and those she judged unworthy she would simply destroy.

For all that machinery, an emotional layer lurks underneath. When she perceived Gaburi's dread of the darkness in humanity, taking the shape of her own recreation of Blackbeard, fear gripped her so hard that she reshaped him into the Doom Guardian to defend herself. Even so, she kept to her flat, robotic delivery throughout. In the end, Gaburi guided her toward grasping human nature, and she finally released her fear.

While immaterial, she can whisk people away into a private black void built around her orb. In physical form she sprouts endless vines of all sizes, some reaching miles, robust enough to restrain a ship the size of the Thousand Sunny, though blades of Zoro's or Brook's caliber slice through them easily. Her core is far tougher, untouched by Luffy's ordinary strikes, and it can reel beings inward through a kind of tractor pull. She also commands creation itself, converting Orbs into living creatures such as Gaburi and reshaping them, based on the data they collect, into anything from a wish-granter to a deadly menace. She can even take that further, studying the gathered data anew to push the Doom Guardian onward into a new stage, the Demon of Doom.

Called a vessel that holds people's thoughts, she scans and files away memories to amass information, drawing not only on her candidates but on their faraway associates too, which let her reconstruct figures like Enel and even the Automatas she had never met. From such data she grows giant seeds that bloom into fully formed custom islands, fields shapeshifting Mud Puppets, and raises trees that fire seeds spawning copies of strong fighters complete with their powers, memories, and personalities, though these duplicates fall well short of the genuine articles. As a last line of defense she can whip up island-sized water cyclones that no vessel can push through.