They were probably eunuchs. Castration causes a delay in the fusion of the long bones in the legs, so they just keep growing.
It’s not just leg bones though, is it?
The size of that hand in his shoulder.
Castration is an interesting theory, but it looks closer to a growth hormone cause. That said, there are around 3000 people alive today that are as tall without any such cause.
It could be natural for sure. The castration theory was just a possibility, considering the date and their profession.
So assassins creed is accurate after all!
I wonder if the professor is really small, or are the guards giants?
One of the giants was 7’9” tall (2.36 m) while the “shorter” one was a mere 7’4” tall (2.23 m) and according to various sources they were indeed twin brothers. They created quite an impression at the Durbar as they literally stood heads and shoulders above the rest. The brothers were known as the Two Kashmir Giants and were elite riflemen in the service of the Maharaja. https://rarehistoricalphotos.com/kashmir-giants/
So ya they were pretty big.