(18+) Universe Adventurer (a massive harem x oc)

Before the war of Gallifrey there was a newly born time lord but as he grow he became the first 18 year old time lord who hasn't age since then however as he became a fully adult timelord he met a fellow time lord known as the doctor.
However a few years later the war started that lasted for a long time til the doctor and the 18 year time lord stole the box that is an end to everything yet the 18 year didn't stay as he left to explore and save lives in another reality where his adventure is just the beginning.