Dr. Spector

Dr. Spector is a friend of the Avatar on Earth, and as the name says, an academic. He also is an adventurer.

Spector was thrown to Eodon together with the Avatar in Savage Empire, and his mind had to be restored before he would help on the quest (before that he was actually a threat). In the end, he returned to Earth together with the Avatar. Spector also stood at the Avatar's side in Martian Dreams, being very helpful in the quest on Mars 100 years in the past. He returned to the present with the Avatar in the end.

Trivia

 * This is, of course, Warren Spector's alter ego.