Berserker (Lu)

Someone whose true name is hard to guess at first glance. A mysterious Servant. He is big, and strong.
…Just who the heck is this Lu Bu anyways? Really.
Although he has lost his sanity, he possesses a tall, strong body, and appears as the majestic general he is in his brilliant armor.
His master is Rani VIII.
As is the fate of those in the Berserker class, his lines are all just incomprehensible yelling, so we don’t know what his real personality is like.
The early designs of him included him being a half human, half horse centaur, or even him as a mech (which was too tough to work out), but in the end we had to go with the true-to-form pure ancient Chinese-style Lu Bu.
All heroes who are summoned into the Berserker class lose their mind in exchange for a strengthening of their parameters, and as a result they also lose the ability to use most of their special trained skills.
This Berserker has lost all his martial arts skills from when he was alive, but in exchange his Restless Soul skill has been sealed away. “Restless Soul”1 means the disposition to defy one’s lord, but as long as this nature is sealed away, this Heroic Spirit will never betray his master. It can be said that this is a rare case where this features of the Berserker class is being employed correctly.
…at least theoretically.
It is questionable whether this warrior is tempted to kill the girl [Rani] who resembles Diaochan, the wife he madly loved when he was alive.

Translator's Notes
  1. ^ Also known as “Defiant Nature” or “Nature of a Rebellious Spirit.”
Fate/EXTRA Material: Encyclopedia of Fate/EXTRA