First of all, I’m not talking about if Cortana should back in halo 5. We do know that Cortana combined with the Mendicant Bias in High Charity. That’s may another reason for her split-personality because the Mendicant Bias‘s thinking ability has already been damaged ( Maybe there was Mendicant Bias talking with Master Chief When Cortana became crazy because she mentioned “that -Yoink-”.) So is there any possibility for a part of the Gravemind combined with Cortana through the Mendicant Bias? Is that possible for the Master Chief goes back to the Ark and tries to find the terminal of the Mendicant Bias to find any message about Cortana (Cortana said that she knows the way to destroy the flood without halo and I think the flood should back in the game as well as the Gravemind because The Precursor’s test to the humanity is not end.).
Just for discussing, we won’t know anything until the 10.27.Sorry for the poor English 