[chaos_alfa]

Originally Posted by DragoZERO

I think my favorite addition was Saber and Iri when they arrived in Japan from Russia. One notable thing was they mentioned how Saber cannot change form like the other Servants. I totally forgot about that. I think it's just a plot device so we see her more.

Actually this was explained in the visual novel.

Spoiler for TYPE-MOON Wikia:

Saber made a pact with the World as she was dying; she would be allowed to try and obtain the Holy Grail to grant her wish. In exchange, if she succeeds, she will finish her life and become a Counter Guardian after her death, a sub-category of a Heroic Spirit at the service of the World. Because of this pact, she is in fact still alive and "frozen" in her dying state when she travels through time to obtain the Grail, and is summoned as a Servant in the Grail War. After each Holy Grail War, she goes back into her dying body, unless she wins or gives up, ready for the next Holy Grail War. Since Saber is not dead, she cannot dematerialize herself. This is also the reason she is able to retain her memories of the events of Fate/Zero, something a Servant should not be able to do (with the exception of Jeanne d'Arc). After giving up on obtaining the Grail and terminating her contract with the World, she goes to Avalon rather than being removed from the cycle of transmigration to be placed on the Throne of Heroes like other Heroic Spirits. She is still considered a person in the present among the English as the "future King who will be back."