He can not be seen unless he wants to. He can not be touched even if he wants to. He can watch but sometimes he doesn’t want to.

Observer has seen many of humans best and worst moments through history. Mistakes were made, wars were fought and successes were achieved. He watched and he learned.

Even though he can go anywhere he wants in the blink of an eye, he can not be everywhere at once. The inability to help everyone, made Observer bitter and he decided to stop trying. But after a while that didn't feel right either.

Now he only interacts on a personal level unless there is a global incident about to happen that must be prevented.

He is without physical form but he can make visual illusions. That is how he interacts with humans now. With images that seem absolutely real.