The best way is to use level up! If you previously summoned Horus LV8 properly, and he is then destroyed, then there's a quicker way to bring him back, you can use Level Modulation.
Horus Lv6 says, that at the End Phase of the turn in which it destroys a monster by battle, that you can send it to the graveyard to special summon Lv8. This means Horus Lv6 must still be on the field after the battle phase, all the way to the end phase. If it gets destroyed during the battle phase, then it cannot summon Lv8.
Monster Gate can special summon them. They are normal summonable monsters, like any regular Lv8 monster. While there is a way to special summon them using Pyramid of Light, that's only an option - they can be special summoned in other ways, such as Monster Gate.
In a way; Horus was considered the current living Pharaoh.
the best way is to get the "machine emperor" cards which are a bunch of anti-synchro union cards
It is a fake card, there is no way to summon it.
I would say an Ibis is the best way to level summoning in terms of Shards used and exp given.
There is no way to do that.
the right way
The only way you can summon monsters is from monster bags, and CPQ, and CPQ2
no because it can't be special summonned and that's the only way to summon a card from a deck.
Horus was one of the big gods and (supposedly) so was Anubis. Really they are both (step) brothers so they must be on the same level of power. (In a cool way...Anubis is cooler then Horus or that's my opinion)
The eye of Horus looks like it does because when he fought the god Seth he lost an eye so the drooping eye is suppose to be the blood of Horus's eye.