So at first, let's talk about backgrounds of my world:
In my world, God is not omnipotent. God gave up his omnipotency in spite of creating the truth values (Falsity and Truth).
He is still in charge of spiritual works though. For example, deciding whether a person must go to Heaven.
Afterlife and stuffs
The only place of afterlife is Heaven. Hell doesn't exist. If a person/spirit is rejected from going to Heaven, they reincarnates. Possibly to a worse life.
If God thinks it's worth it, God encrowns a spirit into an angel. Angels have their missionaries, given by God.
There is no Satan/devils/demons or whatever evil supernatural beings.
General concept of stories
Scientists were encrowned to angels. They have a variety of missions, but ultimately, they want the Reality and Heaven to unite.
Questions I attempted to create
There are so many "questions" I had in mind, but it seems most of them can be answered myself:
Q: Why would angels focus in their missions if Heaven allows them to behave freely?
A: Because only people who devoted in their missionaries in their life were encrowned, and they will devote while in their afterlife, too.
Q: When would God allow angels to directly impact the Reality?
A: When Technological Singularity comes.
Q: How would Isaac Newton, who is now Angel of Force and Embodiment of Classical Mechanics, teach Joseph-Louis Lagrange?
A: Teach him when he is not even born yet.
It seems that I can have questions that focus on small details, though:
Tentacles being also electric cables?
I have talons that can turn into propellers. Can I fly like a plane?
How can I breathe gravitational wave?
But still, I want to start by a question that focuses on religious stuffs. What are good examples?
@JBH has a point. So here are the "rules", chronologically:
Modern Age: Scientists are just encrowned to angels. The can preform "magic" in Heaven, but they cannot affect the Reality. There can be indirect effects, though. For example, Issac Newton and Joseph-Louis Lagrange above.
Contemporary Age: As of Y2K, many great things happened in the Reality, such as invention of computers, aircrafts, internet, and articitial intelligences. Angels worried about them, for people who concerns about philosophical problems became fewer and fewer. Meanwhile, angels now don't rely on magic too much, and they try to solve problems with technology if possible. Spiritual works still require magic, though.
Future: Technological Singularity has come, and a few angels has invaded the Reality accordingly. People in the Reality was startled by that. The Reality and Heaven haven't united though, for there are still problems in Mathematics and Physics. Magic and technology are now indistinguishable.