Don't believe to what Indi says
3SoD (lol, you actually used my own way to short show the name?) is close to be independent game, having almost nothing to do with Laxius Power 1, 2 and 3, because, as he said - it is more based on his book 4 Stars of Destiny, while Laxius Power is only based on it and goes on almost fully altered way.
Also - it would be crime if one doesn't play Laxius Power 1, 2, 3, mark my words