Asmodeus is the first demon to come to earth and the most powerful. When he came XCOM was waiting for him to take him down and study him. But he fled leaving his "first born" Demon child to take the fall which ended up having him Staked to a cross with Demon drills and his lower half cut off to study him. Asmodues has been stuck on Mars in a frozen state which no one knowns about.
Coyote is known as the forgotten one since he was the technical first offspring of Asmodeus but was captured by XCOM and he is more powerful then his brothers but he is stuck in a state of time from his cross. Azazel is the actual first born Demon to come to earth and make a deal with the humans. Since they know nothing of Coyote. Abaddon is the second born Demon to come to earth to join ReGen. Bile the third born to come join ReGen. The rest of his children are unknown but othe Demons like Angels come to earth to destroy but either XCOM, ReGen or Angels stop them.
Coyote is known as the forgotten one since he was the technical first offspring of Asmodeus but was captured by XCOM and he is more powerful then his brothers but he is stuck in a state of time from his cross.
Azazel is the actual first born Demon to come to earth and make a deal with the humans. Since they know nothing of Coyote.
Abaddon is the second born Demon to come to earth to join ReGen.
Bile the third born to come join ReGen.
The rest of his children are unknown but othe Demons like Angels come to earth to destroy but either XCOM, ReGen or Angels stop them.