Who are attacking sanctuary, and why?

Question

I've played all the games and I like the gameplay, never really got the lore. So far I understand that there are demons and angels, and those are in an eternal battle. Inarius, a great angel, was captured by the demons and released by Lilith, a great demon, daughter of Mephisto, one of the three prime evils.

They together created sanctuary and had a bunch of babies(?). Angels and demons had babies and those are called Nephilims. I'm a nephilim in the game.

However it seems Sanctuary keeps getting targeted and attacked, I guess mostly by the demons as it seems I ally myself with the angels(?).

Why do they keep wanting to destroy sanctuary? And why is it only the demons and not the angels?

Answer 1

The story is long and detailed, but here is a brief explanation. It's been a while, so some of recollection is a bit hazy.

The war between heaven and hell has been waged for an eternity. Some of the angels and demons became tired of fighting. Lilith used the Worldstone (a fragment of Anu's eye - their version of God who is now dead) and created the world of Sanctuary. She and her lover, the angel Inarius hid it from everyone else. the angels and demons who were tired of fighting settled on Sanctuary and started having children with each other. Eventually, heaven and hell found out about Sanctuary, but agreed it was off limits. However, the Prime Evils, like Diablo were not going to keep that agreement. In order for Diablo to come to the world he started influencing a priest to find a host for him to possess. This is why the story takes place under the church.

I won't go on, as it spoils the game.