Explain e for me please! Its so fascinating!

Ive just been introduced to e and im fascinated. I'm soo amazed and shocked and can't seems to wrap my head around it that there is a constant that explain all growth and decay with such a massive impact on calculas.

Why is there such a property that seems to explain all? And why does e^x have the property of being the same for value, gradient and area under a graph?

And what is up for euler's identity? Why is it often regarded as one of the most beautiful equation in math?

Someone had also mentioned that it is complex with imaginary part = 0, is that true?

Please explain with more digestable term that a normal high schoolers would understand if possible. Thanks!