the guy with purple hair, AKA San Heath, AKA Zenneth
He is a time traveler.
Jason Scott-Harris and Carston Hawthorn are about the same age and meet several times when they are young, because they are distant cousins, but they do not get along. Carston both admires and dislikes Jason, and resents him. Jason thinks Carston is annoying and wants to avoid him mostly. [Jason is very much a loner, so this is not really personal] Carston resents Jason's disregard of him.
The protagonist of the "a gift of time" series, at the beginning Carston is a teenage boy with long purple hair. He lives at ESM, rides a skateboard, and likes to draw.He is the grandson of Sherman Hawthorn III , who was the son of Emily Hawthorn [Stone]'s brother Sherman Hawthorn Jr.
Carston's father died before Carston was born in a colony ship he was traveling with which disappeared entirely. He lives near ESM because his mother works at the medical clinic there. when he turns 16 he receives a timed-delivery package from his grandfather, who was a time travel researcher. In Carston's time , time travel research is not legal. The package contains the key to a storage locker and the locker contains an electric guitar with pictures painted on it.
Trying to learn about this gift sets him off on a life-long illegal journey through time, In which he loses his wife Sharae in the past and spend most of the rest of his life searching for her trying to find a way to bring her back.
He Disappears from ESM in his early twenties and reappears 7 years later as a scarred 50 yr old called San Heath, with a young man named Joshua who has the memories of 7 other men but none of his own. Joshua was a soul stealer employed by Gaia to travel through time stealing the souls of Dying warriors, but with the help of two Gaian brothers, Alazar and Luciente he has escaped Gaia. His time travel system is different than Carston's, so he is able to return to the time when Sharae was lost. It turns out she was lost at the creation of leviathan, a creature which later became the monster Gaia. Joshua is not able to rescue her at that time,so it turns out they need to uncreate Gaia to rescue her. and it turns out that is going to be done by Emily Scott-Harris, so what needs to be done then is they need to create all the necessary conditions in the past to produce Emily Scott-Harris in the future
The last book of the gift of time series connects together all the differant series...gift of time, savior of homeworld, Lynzee's fountain and Destiny of dreams. It is in this book he gains the name Zenneth, which is the name of the mythical creator of D'zeron. In this book Carston goes to D'zeron near the end of Jason's life when he is depressed after Serai has died, kidnaps Jason and forces him to go on a journey through time with him creating various things that Carston realize have to have been created by Carstons bumbling efforts at time travel when he was younger, except He knows he hasn't yet created those things.
they also plant the first human population of HomeWorld.
at some point in this journey they also meet Sherman III and tell him the things he needs to know to know what he needs to do to leave the guitar for Carston, which means stealing the guitar from Emily Hawthorn at a specific point in her life.
Carston will appear breifly in every book, often just as a guy with purple hair, [for example, Gloria notices a baby with purple hair in the mexican village when she first passes through ESM to go paint the mural] and all those events will be mentioned somewhere in the gift of time series