Will raising level one legendaries screw-up your game for X?

Question

I was wondering since I recently got a level one Arceus, and plus I always see lower leveled legends in the GTS alot like Zeckrom, and Rreshiram even Mewtwo.

Answer 1

Not as far as anyone can tell.

If there are level one legendaries, there is a good chance that they were hacked, but there usually is absolutely no problem raising them. The trouble you run into, though, is trying to breed hacked Pokémon. Just don't do it.

And if they're not hacked, you can (obviously) feel completely safe with raising them as well.