Gate: Thus S.A.T.O Fought There

IW/AW and Halo - Gate Crossover S.A.T.O Infinity was exploring the vast distance of space, when they discovered a earth like planet in the Sagittarius Dwarf Elliptical Galaxy. There they spotted a strange structure known as the 'Gate', where it leads the soldiers of the empire to another world. A world 500 years back...