I'm trying to remember the name of a manga that I read some time ago, but I can't recall it.
It was a Sci-Fi manga about really powerful aliens invading the solar system and humanity fighting a losing battle. It took only 20 aliens to destroy the Earth, and they did it in a shonen-style physical beatdown. The aliens themselves were weird and relied on a ship to support themselves in. The ship was nigh-indestructable though, so humans had to infiltrate it in the inside. However, the problem was that the aliens eventually started to mimic human forms, complete with the memories and personalities of the victims that were brought inside. In addition, the aliens were called the "white ghana," or something similar.