The books are often split in two parts, due to the size required by Japanese ideograms. That's why there is a line in the middle of each "cover", in fact it's a scan of two books set one next to the other to form the full drawing.
The artist who drew those NJO covers is named Tsuyoshi Nagano.
For the record, Dark Tide 1 : Onslaught was called simply Dark Tide in Japan, and Dark Tide 2 : Ruin was called Invasion of Ithor. Star by Star being quite a large book, it required to be split in two parts (which individually consist of two parts each), which are called Star by Star : Predator and Star by Star : Fallen.
Rebel Dream rebeldream1.jpg
Dark Tide: Onslaught onslaught1.jpg
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