Right...

Obviously this is incomplete, but as such that makes some of the inherent problems with a beginning like this all the more apparent.
TOO. MANY. CHARACTERS.
You may be able to develop and use them later on in subsequent chapters but right now, we don't need to know the individual names and descriptions for them, at least not for so many. All that time spent to talk about the characters when the two most important ones are blank except for a little detail on their hair. It's also not even clear what age group they are in. The blonde and orange bimbos may suggest high school but it isn't specified.

As for the supernatural aspect... kind of revealed the nature of both protagonists pretty quickly. It could have been teased with a bit more, kept the reader guessing what makes them different. The actual nature of Nephilim is relatively lacking in explanation, but are often considered to be giants and/or mighty warriors. So far they just seem to be kids with social issues. I know, early chapters, but that just means that the reveal could have waited until it had some meaning.

The names of the protagonists are obviously unusual. Loki for a girl is one thing, but also Akira when his family name doesn't show any indication of being Japanese is unusual. A reason for the unusual names or some supernatural link to their names would be good in subsequent chapters (just going to say that the trickster God was known to either masquerade as a woman, or outright change gender).

All in all a good start, but until the rest is filled out in later chapters then certain things are going to seem very unnecessary, even if it's very important to the overall narative in your head(s).