It seems that the new "Attack on Titan" chapter — chapter 87 — will give light to the mystery behind the titan Zeke's power to assert his will over other titans. Additionally, some rumors are pointing out that the identity of the ninth Titan could be none other than Eren Yeager.

According to the Parent Herald, the new chapter of the famed manga will primarily focus on picking up on Dr. Grisha Yeager's story on how he got involved with the Titan wars.

As most fans can remember, the previous chapter has shed some light on the history of the doctor through the book Eren and the others found in his basement. The book further reveals the identity of Zeke, who is the child of Dr. Yeager and Daina Fritz. 

What this implies is that Zeke — who has the blood of the royal Fritz family — is considered to be a royal Titan who possesses one of the strongest powers a Titan could ever have. A lot of fans are speculating that the royal blood running in this Titan's veins will allow him to control other Titans.

Also, ancient Elodians were remembered as the people who first wielded the powers to become Titans. However, the Marley government stole the powers, and according to the memories of Dr. Yeager, the titan powers have been split to nine, seven of which already under the control of the Marleys.

It does not say, however, if whether or not the two Titan powers left are still under the Elodians' control at the manga's present timeline.

However, Game N Guide reports that some rumors are saying that instead of Zeke having the power to control other titans, it will be Eren who will possess the power instead. After all, it is theorized that the main protagonist of "Attack on Titan" will have the blood of a progenitor titan in him.