The Razielim were the vampire clan descended from Raziel. They have not yet featured in any game; they were referred to in Soul Reaver, but not by name.
When Raziel was one of Kain's six vampire lieutenants, he, like all the others, had a clan. Following the naming conventions in Soul Reaver, it can be assumed they were called 'the Razielim', or perhaps 'the Razelim' as the letter i in Melchiah's name was dropped for his clan: the Melchahim.
In Soul Reaver, Raziel was condemned to the Abyss upon presenting his newly-grown wings to Kain. However, Raziel wasn't the only one to suffer for his transgression. Following his execution, the Razielim clan disappeared from Nosgoth.
After his return from the Abyss, Raziel revisited his former stronghold, "anxious to see how [his] descendants had fared during the centuries of [his] absence". The Razielim territory was to the west of the Abyss, next to Melchiah's territory: the Necropolis. He found it desolate; his "once proud kin, wiped from this world like excrement from a boot". There were some of the Dumahim there, but none of Raziel's clan.[3,4]
Raziel immediately held Kain responsible, and he questioned Melchiah about the fate of the Razielim during their encounter. Later, in the Sanctuary of the Clans, he expressed his outrage to Kain himself. Angrily, Raziel said that the genocide of his clan was "unconscionable". Kain was unremorseful, and retorted that Raziel was not in a position to question his judgement about the matter. What Kain had made, he could also destroy.[4,5,6]
There has been speculation amongst Legacy of Kain fans that some of the Razielim may have survived, in one form or another. If they did, and if they appeared in a future game, it is assumed that they would have followed Raziel's evolutionary path, eventually growing bat-like wings like his. All of the clans in Soul Reaver evolved in a similar manner to their lieutenant-patriarch.
Melchiah's comment: "Do you believe for a moment that our Lord would risk his empire upon an upstart inheritance?" may suggest the Razielim rebelled against Kain's rule following Raziel's execution. Alternatively, if they had started to develop wings - or there was a chance they would in the short-term - that alone would make them guilty of the same transgression as Raziel: surpassing Kain. It was a crime they could not help committing, and it would justify their annihilation (or exile; we don't know for certain what happened to them).[1,5]
We know from Defiance that Kain's execution of Raziel was really part of Kain's larger plan to "reshape [their] inevitable futures". Whatever Kain did to the Razielim, he must have believed the ends justified the means. It may be that he simply didn't interfere if and when the other clans turned on them. He seemed disinterested in holding his empire together in Soul Reaver.[7,8]
We saw in Soul Reaver that the evolution of the clans diverged greatly after Raziel's execution. All of the clans could have been deemed guilty of 'surpassing' Kain's evolution, as he appeared to have reached an evolutionary plateau, at least physically. Initially, Kain may have always experienced evolutions before his lieutenants, but there seemed to be a tipping point, at which the corruption they inherited from him triggered their rapid devolution into monsters. Kain was not affected by his corruption in the same way they were.[1,9]
- The Soul Reaver Game Manual (UK and US versions)
- [SR1] Raziel: "Kain would enter the state of change and emerge with a new gift. Some years after the master, our evolution would follow. Until I had the honor of surpassing my lord. For my transgression, I earned a new kind of reward... agony."
- [SR1] Raziel (referring to the cliffs surrounding the Abyss): "Though much of Nosgoth's landscape had changed, these cliffs gave me my bearings. My clan territory was to the west - I was anxious to see how my descendants had fared during the centuries of my absence."
- [SR1] Raziel: "Utter desolation. My once-proud kin, wiped from this world like excrement from a boot.
I knew the hand that wrought this deed..."
- [SR1] Raziel: "What has become of my clan? Answer me, little brother, or I will beat an answer from your horrid lips."
Melchiah: "Everyone is afraid, sibling. You awake to a world of fear. These times of change are so... unsettling.
Do you think I feel no revulsion for this form? Do you believe for a moment that our Lord would risk his empire upon an upstart inheritance?"
Raziel: "Enough riddles - what are you saying?!"
Melchiah: "You are the last... to die..."
- [SR1] Raziel: "I am your creation, Kain - now, as before. You criticize your own work.
What have you done with my clan, degenerate? You have no right -
Kain: "What I have made, I can also destroy, child."
Raziel: "Damn you, Kain! You are not God! This act of genocide is unconscionable!"
Kain: "Conscience...? You dare speak to me of conscience? Only when you have felt the full gravity of choice should you dare to question my judgment!"
- [DEF] Kain to Raziel: "Because of your remaking, you are the one unbound creature, the one among us all that truly has free will."
- [SR2] Kain to Raziel: "You have the power to reshape our inevitable futures."
- The second Defiance Q&A page at The Lost Worlds