You can use "Star Blast" to reduce the level of this monster to 6 and Summon it with only one tribute.
This card works very well with Majestic Mech monsters. If "Angel O7" is on your side of the field during the End Phase that the "Majestic Mech" was Normal Summoned, its effect cannot activate and it will not be sent to the Graveyard.
Have this card on the field along with "Silent Swordsman LV7" and "Royal Decree" to negate almost all card effects and have an only monster battle.
"Angel O7" is a perfect counter against many decks, including Lightsworn decks, whose Ignition effects mill to pull out their cards, and Gladiator Beast decks, whose effects return their "Gladiator Beasts" to the deck to Special Summon others. This strategy can only work though if they do not affect your own monsters as well, so add this card to a deck with dominantly Continuous effect monsters or Normal Monsters.
This card would be very useful against "Stardust Dragon", since it prevents the activation of the effect.
This card can work with "Chimeratech Overdragon", because it prevents the activation of the effect of "Chimeratech Overdragon", which sends all other cards you control to the Graveyard without negating its ATK gaining effect and multiple attacks effect.
In a "Constellar" Deck, this card can be very useful when combined with "Constellar Belt". All of your LIGHT monsters will be able to use their effects without any inhibitions. This is especially valuable if you main "Royal Decree", allowing for an almost complete defense against any counters your opponent may have in store.