Mole is widely known for being the spicy sauce with chocolate. That is true but partially as there are many kinds of mole. Mole is the generic name for the thick salsa made with a lot of ingredients, it would be the equivalent of curry in Indian gastronomy.
In this particular case I´m showing you the one that goes with traditional Enchiladas de mole. This one is dark brown with tints of reddish. Depending on the recipe there can be as much as 8 to 10 different varieties of chiles, ranging from pasilla, morita, ancho, etc., it all depends on the region the mole is from, which ones are more easily available, and of course affordable. You also have chocolate of course, but don´t think you will be pouring MilkyWays and M&Ms, the true chocolate has very little sugar; you also have platano macho (plantain) as a great addition to the flavor and consistency of the sauce, you fry it and the mash into a paste before adding it to the mix.
The mole is not exactly an everyday dish in small towns, it is festive food for the gib occasions, like a wedding or to celebrate the birth of a son, on those days it would be Mole with Guajolote (the local turkey) which is tastier and more expensive than with chicken.
Now with modern transport and economy is easier and cheaper to get the ingredients and so you can have a plate of enchiladas de mole on an everyday basis available for any small restaurant.
The mildness or hotness of the mole depends on the recipe and the cook. Normally mole negro is not that hot, it may rank in the middle of the scale or lower, but if you find it too spicy for your taste you are advised to sprinkle some sugar.
Buen provecho.