so if i have lv 8 horus in my grave and didnt summon it in any way previously i can do so with that card? also if i have him out of play never previously summoned can i use d.d. master to bring him to the field?

Yes, because level modulation ignores the summoning condition, but you cannot bring him back with D.D. master since its cannot be special summoned exept by horus lv 6

Actually, in your given scenario, it would not be possible to Special Summon "Horus the Black Flame Dragon LV8" through the effect of "Level Modulation." Straight from the official UDE website:

1. As the ruling above states, the nomi LV monster MUST have been properly Special Summoned if you wish to use Level Modulation on it.

If it was.....

A.) Discarded to your Graveyard
B.) Sent from your Deck to your Graveyard
C.) Special Summoned via Level Up!

...then you cannot use Level Modulation.


2. No, you CANNOT Special Summon the nomi LV monster's in ANY way except through their previous LV's or, as Level Up! and Level Modulation state, it specifically states that it ignores Summoning conditions.

D. D. M. - Different Dimension Master does not ignore summoning conditions, so even if you properly Special Summoned the nomi LV monster's, you could not Special Summon them back except through the proper usage of Level Modulation, which only works with your Graveyard anyways.