Count Nicholas Cogliostro was once a Hellspawn. He then found a way out of the deal with Malebolgia. As a result he became human again but was scarred with the mark of a Hellspawn upon his body appearing as the M all Hellspwan have branded on them. He was left with only a limited amount of power, if he used this power however he would be sent back to Hell. Cog has never used any of his power and as a result has been alive for centuries. Cogliostro has lived through important events in history and even fought during the Medieval Era. During this time he encountered the Hellspawn of those periods and did what he could to help them free themselves of the curse.
Recently however that all changed. When Spawn reentered Hell Cogliostro met with Mammon who gave him a box. Upon receiving the box Cog committed suicide so that he could enter Hell to help Spawn. When he entered he revealed to Spawn that he was actually Cain, the very first murderer and that he had used Spawn to get to Hell and take it over. He then took over The Eighth Sphere of Hell and sent Spawn back to Earth with his original body and face.
The Tower to Heaven
Once Cain took over Hell he used its vast armies to construct a massive tower that pierced the very sky. Cain later gave control over the Eighth Sphere to more powerful demons. Cogliostro was planning to use the tower to climb up to the heavens and give Hell the chance to finally attack. This story arc is still in development.
Cogliostro along with Medieval Spawn and Angela was created by Neil Gaiman and Todd MacFarlane. Neil Gaiman was asked to do one issue of Spawn and in that issue he introduced the three characters. After that issue MacFarlane kept using the characters in various issues and Cogliostro was also featured in the live action movie and animated series.
However, MacFarlane told Gaiman that he had the ownership of the characters but later changed his mind, saying that Gaiman was hired to work and claimed that he owned them. Gaiman brought it to court and won. The characters are now owned by both men in a 50/50 split.
Appearances in Movies
Spawn (1997, Live Action Movie)
Cogliostro appears in this film. This version from the movie was quite similar from the comic book version, but he did lack a few notable characteristics. He was portrayed by Nicol Williamson.
Todd McFarlene's Spawn (1997-1998, Animated Series)
Cogliostro guides Spawn in this mature animated series presented by HBO. He was voiced by Richard Dysart.