Kingdom Hearts III's 9th day countdown media shows Riku talking of protecting those who "still have their hearts"

Ok this gives me hope but... Who might say this? If we base our thoughts on what we saw in the Final Battle Trailer, then there shouldn't be anyone else to act this quote... and it doesn't sound like Sora... I wonder...

This could mean anyone. Several characters are going to be in distress come the 29th. I mean Riku is literally talking about everyone currently lost with a quote like that.

This adds more questions, but at the same time I feel like I don't want any more information until the release day.

I wonder if we get to take control of Riku more than one time during the game, and this is one of those times.  We see Riku protect Sora from a wave of Heartless while Sora is on his hands and knees near the end of the Final Battle Trailer.  Maybe Riku says this quote to Sora, but Sora is too upset by what happened, so we play as Riku as we try to protect Sora from the oncoming Heartless.  It could end with Riku being lost to the storm of Heartless too as he sacrifices himself to save Sora, which leaves Sora all alone.

It is also possible that he says this before everyone is swept away by the Heartless, which would mean that he is referring to Donald and Axel (and possibly some others who haven't been shown yet) and is telling everyone else (Sora, Kairi, Mickey, Goofy, and whoever else could be there) that there is still a chance to save them.

I suppose he could also be talking about one or more of the characters who have been Norted and is saying that there is still a chance to save them from Xehanort's control, but I think that the other guesses are more likely.

Thank you for sharing this with us, KHWaterBlock! 

What could Riku be referring to with this? :o Dang, I seriously can't wait to play this game already! The hype continues to elevate! I'm sure that he's referring to the ones that must be saved, like Aqua, who still has her heart, but is simply lost to darkness. So interesting!