Thutmose was born in the far future. He travelled back in time and became an Egyptian pharaoh. (PROSE: The Three Faces of Helena) He ruled his people with wisdom and kindness, and fought his enemies with a mighty sword and lion's courage. (PROSE: The Three Faces of Helena)
When Erimem tried to stop Ibrahim Hadmani's death several times on an ice planet, each attempt resulted in a new way for him to die. Her grandfather came to her in a dream and after she was able to go back in time and prevent Ibrahim from going to the ice planet in the first place. (PROSE: The Snow Wolves)
Thutmose showed Erimem a variety of possible pasts and futures. The lesson he wished to impart to her was that time was fragile, and that if she had to change the past, she should only do it once. Any more times would cause irreparable damage to time. He used her changes to time on the ice planet as an example. Erimem said that she understood, and Thutmose expressed his hope that she did. (PROSE: Echoes)
Thutmose visited Erimem when she walked the tomb of her father after his death. The tomb threw many challenges at Erimem, yet when she was told to surrender, she stood and fought the apparitions that attacked her. Thutmose told her that she had an important place in history, and had to take the position of pharaoh, albiet briefly, otherwise history would change and the universe would be torn apart. He then erased her memory of what had transpired in the tomb.
In 272 BC, when Helena gained her immortality, and had been stabbed by Queen Asha, she was dragged downstream by a river, and eventually washed up on a riverbank. Thutmose appeared and led her to food and water, places where she could steal clothes and then onto other places where she could be educated and prosper.
Thutmose guided Erimem in the days before she discovered Helena's secret. He told her that Queen Asha was the greatest threat the world had faced. He also showed her that Earth's future would deviate due to these events, and in 2419 a fundamentalist cult would take control. This future would lead to the end of humanity, and guided Erimem towards averting it. (PROSE: The Three Faces of Helena)