God Cards ruling

I want to ask about someting that occured at last battle of Yu-Gi-Oh! in battle between Yugi and Atem.

Atem summoned Slifer along Queen's Knight and King's Knight with the effect of Summon Clock, which is a Special Summon. And if I remember right, in the anime if God Card is Special Summoned it is sent to graveyard at End Phase (but maybe that occurs only for spell cards?).
Other thing is that the God Cards have they're hierarhy, right? So The Winged Dragon of Ra should not be affected by Slifer's ability...

Can anybody explain it to me?

television bull shit they don't actually have to follow how the game is played or make sense from beginning to end

well they only stay in play for 1 turn if special summoned from the graveyard. and there techniqually isn't a higharchy, they are suppose to be equal more or less, only gods can hurt each other. that is why slifer was able to weaken then with his effect i believe.