Although this was never demonstrated in the books, some characters speculated that Doomgiver might also provide protection against the Mindsword.

However, a character speculates that the Species could be literally billions of years old.

Another character speculates she could be 40-45% human, and 55-60% Cyberman.

He is a somewhat feminine man, and his girlish tendencies lead the other characters to speculate his sexuality.

Many characters speculate about how many people he might have killed, and the stories of his past are taller every time they are told.

Some characters speculated on Serrano, who eventually became regent.

Other characters occasionally speculate on the pair's relationship.

Several characters speculate that someone higher up within the Empire may be engineering the elimination of various people who were loyal to the late Emperor.

In a talking heads sequence, characters speculate on where he is now (if alive).

The other characters occasionally speculate that he is a second son of a daimyo but his identity is never revealed.