You know what would be cool?
If the spirit/demon/myth champions that have been released (and the ones that have yet to be released) were based off of the 7 deadly sins. Rito could make so much cool lore behind that. Also some demon skins for the cash money that riot loves.
is the spiritual embodiment of the sin of gluttony. He is cursed with an insatiable hunger that consumes him.
could be the spiritual embodiment of the sin of wrath. He invokes bloodlust in warriors, causing them to destroy their enemies
could be the spiritual embodiment of the sin of sloth. He gives no fucks at all.
could be Lust,
would be Greed and
would be Envy, as far as Pride a lot of champions could actually take that spot... by my vote would most likely fall on 
(Kog'maw fills the spot alongside Tahm)
Wrath:
(Because they pair up so well)
Sloth:
(Because who doesn't love sitting in his turrets)
Lust:
and
(Outrageous)
Greed:
(Zed's unhealthy obssession against Shen and Amumu's envy for the living)
Pride:
and
(FOR DEMACIA)