This page is not intended as a complete synopsis of Madame Web's character, rather, an overview of the events that took place shortly after the Gathering of Five ritual.
Cassandra Webb, aka Madame Web, has served as both an ally and confidante for Spider-Man over the years. But her desire to restore her youth caused her to align herself with Norman Osborn and his upcoming Gathering of Five ritual. She was one of the fortunate members of the Gathering, as she recieved the gift of immortality, but her gift, as with the others, was not exactly what it seemed to be.
When the ritual was performed at Osborn Industries Headquarters and the "gifts" were distributed, Madame Web was thrown to the ground and left with no pulse. The remaining group members believed her to have recieved the gift death, but this was not the case. Madame Web returns to the Spiderverse for the first time since the ritual in Amazing Spider-Man V2 #6, with her youth completely restored, she had actually recieved the gift of immortality.
Madame Web soon begins to serve as a mentor to Spider-Woman III (aka Mattie Franklin), and even gathers all three of the woman who have worn the guise of Spider-Woman together to battle the Evil Spider-Woman. Madame Web would often appear to Mattie in an astral form, helping the young hero in her decision making process but not directly intervening.
In Spider-Woman V3 #2, Madame Web explains her connection to the villainess known as the Evil Spider-Woman. Charlotte Witter, Madame Web's granddaughter, was a fairly reputable fashion designer whom Dr. Octopus had kidnapped and performed genetic experimentation upon. She was endowed with spider-like powers and she soon was forced under the mind control of Doc Ock.
But the Evil Spider-Woman caused a disturbance in the power balance established by the Gathering of Five due to her ability to "absorb" people's powers. In Spider-Woman V3 #9, Madame Web explains that when Mattie had stolen back the powers which Charlotte had taken from her, Mattie also stole the powers Doc Ock had given Charlotte. Since all the members of the Gathering were linked together in some "subtle way", the power siphoning by Mattie brought Charlotte into the Gathering's power loop. So when Charlotte siphoned her powers back from Mattie, she also siphoned the powers of Madame Web, causing her to age once again. The Madame is able to use the power siphoning against Charlotte, who had apparently been utilizing some of Madame Web's telepathic gifts to hypnotize Spider-Man. Charlotte was "feeding on the mental energy of those whom she fought" and when Madame Web instructs Spider-Man and Spider-Woman III how to "blank their minds", she was easily defeated. Madame Web once again had her youth restored and the power balance returned to normal.
Could this "power siphoning" allowed Norman to re-establish his sanity to some degree? That is uncertain at this point.
Madame Web makes her final appearance as Mattie Franklin's mentor in Spider-Woman V3 #14. In this tale, Madame Web helps Mattie battle and defeat the new villain Nighteyes. This is the last appearance of Madame Web within the Spider-Woman series.
The youth restoration that Madame Web had experienced seems to be a volatile gift, as later stories often feature her more aged appearance.
Madame Web gathers Spider-Women I-III together to battle a new threat, as seen in Spider-Woman V3 #1
Left: Madame Web aids Mattie Franklin against the Madame's own granddaughter, the Evil Spider-Woman as seen in Spider-Woman V3 #1
Right: Madame Web's youth is robbed from her as she begins to age once again, as seen in Spider-Woman V3 #8