Ian Kazex. appeared in the episode "The Tale of the Reanimator", he was portrayed by Pierre Auger.
Not a lot is known about Ian Kazex's past, but since he's gravestone said "May he be forgiven!" it can be assumed he
was a ruthless murderer. Also, since he seemed to be pretty young when he was reanimated, it can be asssumed he was either put to death through means of justifiable homicide or execution (possibly hanging since he couldn't talk).
In the wintertime of the year 2000, a scientist named Mr. Doyle had been hard at work inventing a DNA revitalizing serum. Mr. Doyle's teenage employee Julie was worried, he would use it to bring his wife back from the dead.
Emma's older brother Peter, thought she was playing an April Fools' joke, Therefore he wanted proof, so he picked a random gravestone and spilled serum all over it. Ian's grave just happened to be the one that was picked.
Soon enough, Ian Kazex partially came back to life as a reanimated zombie. He couldn't talk he would just grunt, scream and shout. He then went a vicious rampage, and followed Emma, Peter and their friend Jake all the way home.
He did this because wanted the rest of the serum, because it was the only thing keeping him alive. Therefore he got more of it, he may have came back to life completely and go onto another killing spree. Without the serum, slowly his system was expelling the serum from his body as gooey dripping slime all over his skin. Therefore slowly he would die again without receiving more of it.
He kept encountering Emma, Peter and Jake, viciously screaming at them and trying to grab them. Soon Emma thought that if they sprayed him with cold water, it would deplete the effects of the serum. Then he was lowered all the way, outside of Mr. Doyle's laboratory, where they lured him into an icy puddle and then sprayed him with a garden house.
Ian at first, passed out after being drenched with the freezing water. But very soon he got back and was still the same. He was then lowered right into the basement laboratory, where the three teenagers realized they needed hot water and heat to defeat him.
Peter, taunted him, by waving the vial of serum in front of him, and he was lowered into the hot box heated room. When he was locked inside, the room was so hot, he instantaneously begun to wither and dry up and chock back to death. Soon nothing was left of him but his rotted corpse, he was soon likely reburied