Ken Fasta Petrillo, nicknamed "Ken Faster", was a Xenomorph cultist, a member of the Church of the Queen Mother and a Xeno-Zip addict who had volunteered to become a host for impregnation. The resulting Xenomorph, dubbed Mozart, was then planned to be used in Damon Eddington's Symphony of Hate project.
Once a renowned guitarist before becoming addicted to Xeno-Zip, Petrillo eventually lost his fame and became homeless. He soon after joined a group of cultists that worshiped the Xenomorphs.
Believing Xeno-Zip was not enough any more, and wanting to worship at the source, Ken desired to become one with them by allowing himself to become impregnated by a Facehugger. Ken is approached by Ahiro and is convinced to come with him. Ken meets Damon and the latter recognizes him as an old associate. Damon becomes slightly uneased by the reveal of the host being his former friend and questions Ken if he is certain that he wants to go through with it. He confirms he does, albeit he admits he is a little afraid.
Before the two could finish talking, Ahiro takes Ken and sits him in front of the egg that he and his men had stolen from MedTech. The egg starts to open and Ken seemed to have changed his mind, but is held in place. The Facehugger then latches on to him and incapacitates him. Ken is taken into a cell and after enough time has past, he starts convulsing as the chestburster emerges. Upon hearing the young Mozart's shrieks, Damon almost immediately washed away any guilt regarding Ken's death and perceives his sacrifice to have resulted in him becoming one with his 'god' and an embodiment of his music.
In his youth Ken Petrillo was described as having auburn hair and being very popular with females and became a very good and renowned musician. Even before Xeno-zip, Ken had an adventurous personality and enjoyed experimenting with multiple drugs, saying to Damon that if it was out there, he would try it at least once. though he claimed he never got addicted to any of them, not even Xeno-zip at first. Ken described it as not being too much different to any other high and was going to move on to the next drug until he started hearing the "music".
Ken became unhinged due to his addiction to Xeno-zip and he claimed he could hear music while he was on it, these audio hallucinations played a significant part in his homelessness as his performances got worse and he even stopped playing his guitar altogether, having sold it for drug money. Ken believed that the music he heard when he made air guitar gestures was enough and that it was from the Queen Mother, he described the music as being like a choir.
Having become addicted and wanting more Jelly, Ken eventually joined a Xenomorph cult though he didn't appear quite as fanatic as the other known cultists, as Ken retained a reserved demeanor though he was considered almost childlike and overly trusting due to his state of mind. His reasons were explained as wanting to worship "it" at the source and he eventually desired to become one with it.
However, like most Xenomorph cultists, the reality of becoming a host was more than he bargained for as upon being brought to a Xenomorph egg, Ken started to panic and seemingly regretted his choice. However, what reluctance Ken had seemed to have washed away by the time he regained consciousness, as he seemed more concerned and even outright distressed about not hearing the "music" anymore than his impending death, as he was banging on his cell's walls asking where the "music" went.
By the time of his death, Ken was actually near to Damon's age, his aged appearance being the result of years of drug abuse.