How old are the main characters in The Last Tree?

Nova is 18, Terra is 19, and Pax is 20 during the events of The Last Tree in 2325. White Radio One's consciousness (Sarah Chen) is over 200 years old.

What is a Radio Unit?

Radio Units are advanced military AI-human hybrids created by uploading the consciousness of class-one orphans into robotic bodies. They were deployed in pairs — one PAA, one EC — to each protected zone under international treaty.

Characters of The Last Tree

Nova

An 18-year-old orphan classified as a class-one citizen — the rarest and most valuable designation in the system. Nova has intense green eyes that mirror her mother's and a collector's obsession with forbidden knowledge about trees and nature. She carries a neural interface implant she refuses to use until the moment it matters most.

Nova begins the story as a quiet resistor inside the Residential Allocation Center. By the end, she stands before the world as the Arbiter of Protected Zones — not because she sought power, but because she refused to let the last tree become a weapon.

"We are not the classes they say we are. We are what we choose to be."

Terra

Nova's 19-year-old sister and the family's technical genius. Terra is analytical, pragmatic, and always carrying technology. She's being considered for class-three status — a mid-tier designation that would give her a salary and limited freedom. Instead, she uses her skills to hack systems, form an unexpected intellectual connection with White Radio One, and plant sequoia seeds throughout the protected zone.

"We have everything."

Pax

The eldest sibling at 20, Pax is the protector. He wears customized military-grade armor with face plates and has connections to underground networks. While Nova leads with conviction and Terra leads with intelligence, Pax leads with sacrifice — orchestrating the orphanage escape plan and fighting to physically defend both the tree and his sisters.

"Protocol — 'Zashchishchay nas' — Protect us."

White Radio One (Sarah Chen)

An eight-foot military robot with intricate white armor panels and opal LEDs — but inside is the consciousness of Sarah Chen, an orphan from the 2110s whose mind was harvested and uploaded into this body 177 years ago. WRO has guarded the last sequoia zone for nearly two centuries, caught between her programmed directives and her retained humanity.

Her armor panels express emotional states: flush when neutral, angled outward when defensive, pulled tight when vulnerable, full 45-degree flare under extreme emotion. She is simultaneously the story's most dangerous threat and its most tragic figure.

"Because sometimes protection requires them to see the threat. Even if you have to create it yourself."

$imon

A heavily modified maintenance droid with UV-reactive panels, a rectangular head unit, and an LED face plate that displays emotions. $imon is resourceful, loyal to Nova, and street-smart. He carries one defining advantage: he always backs up his consciousness.

When $imon is destroyed, he transfers his consciousness into the discarded chassis of Red Radio One — and uses a dead robot's body to restore global communications from orbit.

"First rule of staying alive: always back up your consciousness."

Red Radio One (Petrova)

The Eastern Coalition counterpart to White Radio One. Petrova's consciousness was uploaded alongside Sarah Chen's, and together they guarded the sequoia zone — until WRO manipulated her into attacking the tree. Petrova is betrayed, destroyed, and left in the stream. Her empty chassis becomes $imon's new body, transforming from a symbol of betrayed potential into something unexpected.

"Empty does not equal worthless."