How many forms of corvus in dq9?

That depends on your religion. Some religions think he is everywhere but no one can see him

Denominations of Christians: Roman Catholics Orthodox Protestant Anglican The Free Churches Pentecostal many other free churches.... baptist, methodist, etc.....

Yes. Think of them as anything moving (including pure energy) or with the potential to move.

Usually 3 but can also form 5 - with Fluorine for example.

Uncountable trillions. Every human, dog, cat, rat, ant, spider, termite, bee and fly? Quadrillions. Add bacteria and viruses; they're all life forms. We can't even GUESS what the number is.