Berserker!

Berserker is the incarnation of Sir Lancelot, he was summoned by Josh and now works as his noble servant in which he must do everything Josh tells him to do.

Appearance
Berserker is a robust man fully clad in pitch-black armor and a rustic helmet with a thinly carved slit displaying the ghastly glow of his eyes. The armor is the work of the delicate and nuanced workmanship of its smith's utmost effort, succeeding in granting it an air of formidability and a fine construction. It is a perfect armor that can be called neither exquisite nor crude, and it instead perfectly melds magnificence and functionality. It is carved with countless marks and scratches, the highlights of his various military exploits etched into it to add a touch of valor. It is an ideal battle outfit that all knights could not help but envy.

During life, he was an ideal incarnation embodying the true face of a "knight." Having lost his distinguished dignity of the past, he has been thoroughly changed by his descent into madness. Mad Enhancement and his anger have corroded him into his pitch-black form. He has a blackened face, the visage of a living dead man who has lost everything to a curse. He had a beautiful visage capable of drawing the admiration of many women, but his hatred has made him gaunt and pallid like a phantom. The only part of him filled with light is his eyes that are filled with hatred. He retains his normal appearance while not under the effects of Mad Enhancement.

Personality
"I am the alienated, the ridiculed, the despised. No need to praise my name. No need to envy my body. I am the shadow under the radiance of heroic spirits. Birthed of the darkness of glorious legend. And so, I hate, I resent. Nourished by the sighs of the people precipitated within the darkness, people that curse the light. This is my disgrace. Because of her unsullied glory, I must forever be belittled. You are, the sacrifice. Good, give me more, your blood and flesh, your life. Let them ignite my hatred—!!"

- Berserker to Josh

In his lifetime, Lancelot was a chivalrous knight who shared the same ideals as his King to save their country from foreign invasion. However, when he had an affair with Guinevere, he and Guinevere blamed themselves for betraying their most important person.

Lancelot is shown to have extreme loyalty to his King, but his guilt was, ironically, compounded by Arthur's refusal to actually blame or reprimand him for his actions. He would later admit that this made him feel it impossible to atone for his sins. In his despair, Lancelot sought escape through descent into madness to seek atonement; thus, when he became a Heroic Spirit, he was summoned as the insane Berserker.

As Berserker, his mind is under the effects of Mad Enhancement, limiting his rationality and ability to think. He gives off nothing but murderous intent and the thirst for blood, his deep hatred radiating out from him enough that he can easily be sensed even when he is hidden. He is able to battle with finesse due to his martial prowess, and he shows the ability to recognize that Ryder has been ordered to help him and take him as an ally for a short time.

He still recognizes his King, instantly becoming hostile towards him and forgoing any orders in order to fight her. He growls parts of her name, a moan full of malice hardly resembling human speech. His hatred stems from his inability to save Guinevere and Saber's legend, for he has to live in her shadow as a prideless traitor.