Ubisoft have revealed that the players will be able to choose between two possible protagonists - Alexios and Kassandra. They are the grandchildren of the legendary Spartan king Leonidas who have inherited his somewhat broken spear.
Ubisoft have revealed a lot more about Assassin's Creed: Odyssey during their E3 conference, including the release date which will be on 05 October 2018. They have also demonstrated to how to present and involve female characters into a game without forcing it down the players' throats. For example, neither Kassandra or Alexios have any mechanical appendages or katanas on them.
Odyssey will also feature a dialogue system but it remains to be seen to which extent it might affect the actual playthroughs, other than romance opportunities. Speaking of which, the Ubisoft presented offers a glimpse at a romance opportunity with Kyra. This particular female character, or at least Kassandra, seems to be bisexual as there is the dialogue option to engage a romance at 5:23 time stamp.
Once again, that's diversity done right, - as Ancient Greece didn't shy away from that were unorthodox at the time. On the other hand, gore is a part of the game Ubisoft maybe didn't get right. There is a with another mercenary at 3:25 where we're presented with a rather brutal finisher at the end of the fight but there is literally no blood in sight. It looks as if Kassandra was slashing an android.
that appears at 6:02 is in stark contrast to the no blood policy though, as Kassandra is seen obliterating a random soldier, with his blood sprinkling all over the beach. This may be a hiccup in Ubisoft's production of the footage for E3 or a gore option that was switched on between the sequences. It's not clearly specified if we will have an option to turn gore on or off though.
In fact, it may be wise to assume the only thing we know is that we know nothing. Just ask Socrates, he will be present in the game.