Im looking for the name of an anime

So im looking for the name of an anime that I got to see 1 or two episodes of looked interesting and I would love to keep watching it.

Here is what I know about it seems to be set in a city and people obtain super power via some kind of internet game they lose powers upon losing a fight and there was some kind of invisible castle on top of a skyscraper.

If anyone knows what im talking about and knows the name of the show I will give much loves.