Mafia 71. Ancient World

It's silly, although amusing. Others essentially have no less chance.

You're lying. The a priori probability of you being the Mana is higher than anyone else's – 16.7% (taking into account the corrections in several posts above).
Naturally, this is far from enough to condemn you, but it's more than enough not to blindly believe.
As for the a posteriori probability, let everyone calculate it themselves; that's where ontology comes into play.

And I doubt that three Mafia members voted. At most, two.

The Mafia won by one vote. They could have lost if they had left one living vote for a non-Town member. They could only have done this if they were absolutely sure about the distribution of "townies." By the way, under this hypothesis, we should suspect those who cast their votes last.
So, we have three votes from the Mafia and, quite possibly, a vote from the Mana plus two or three votes from peaceful killers.