ss
I'm pretty sure he's banned from this mode because his ult has 0 cooldown and no counter. Realistically he's only S or S- though, since if you can cc him and kill him, he has to build up charge again and is useless without the ult.
s+
can carry any game, can destroy most gods easily with very few counters, will only lose because skill diff or the other team has several S tier gods and your team doesn't.
s
can usually carry a team
s-
can usually do pretty well, but struggle against top tier gods
a+
some carry potential, but will need to outplay better gods quite a bit
a
are still good and can occasionally carry, but generally lose to better gods
a-
very hard to carry a game, very little outplay potential against better gods
b
almost impossible to carry a game, very difficult to do anything, often best to just build tank
c
cry