The giant's work was almost complete. His people he carried to their new home, but they did not recognize him as their own. He was so colossal and so ancient that they had no idea that he was younger than some of their ancestors. Even he had lost track of their genealogy. Did any of his friends have descendants here? Even he did not know, and the internet was long gone.
He told them to go on ahead, past the first river that they saw, and to stay there until another met them there. They were reluctant to leave, but they did so, anyway.
This world was maintained partly by the giant's continuous thoughts, which were so integrated that he could not separate them without also separating part of himself. He could not stop thinking the thoughts that he had to think to prevent entropy from ruining this place. He also could not join them as his gigantic self, forever growing. So, he gave up part of himself. He petrified his body to protect his nervous system, forming a small mountain with his arched form, his open mouth a cave hidden between his elbows. He created a body inside of himself from what could be spared of his organic parts. Then, he reconfigured his nervous system, leaving behind his enthropic thought-patterns and the parts of himself that he could not extricate from them.
From the mouth-cave emerged a new man, yet the oldest man still alive, and he headed toward the river, to join the rest of humanity.