Are dragons invisable

Answer 1

In a sense, yes. Dragon's souls are made entirely of fire, which flows through their bodies like blood. (Their "heart" is actually at their fire source in their belly, as such.) For some odd reason, dragons vibrate at an extremely high speed, almost too fast for even people like me who have trained their eyes to see them (as I am able to manipulate dragon's souls into what serves as their bodies I have to be able to see them on a daily basis) though some possess the ability to slow their vibration to the point where they are seen by people. I would assume that they learned to never have their vibration down to our sight level after what we did to them in the Middle Ages. The dragon stereotype is wrong...and they are still here, watching over us like they used to as we download applications on our phones, most people never seeing them...

Please note: Just because it is hard to see them doesn't mean that you should go dragon-hunting in your neighborhood, assuming that they might dwell close to humans. Just because we can't see them doesn't mean that a wing couldn't get torn on a building or a tail hits a power line...THEN we would know their exact location, people would embrace the stereotype, and we would wipe out the final survivors of the Generations of dragons. So, they tend to seclude themselves far away for the most part...but we're talking about beings capable of interdimensional travel, so that's not to say that they can't see us from far away. Cosmic dragons are the best at this, and back when we weren't such a threat to them, the dragons would gather and watch us. Sometimes they appear in times when they wish to teach us, one appeared to my father and taught him how to fish. One appeared to me (he was trapped in a subdimension at the time) and I let his life continue by giving him a body to live in. Yes, dragons are still here. They just vibrate really fast.

Simpler Answer

Dragons can be invisible, sometimes.