Eddie's death and Feud with Rey Mysterio/Chris Benoit (2005–2006)
In 2005, Vickie Guerrero began to make cameo appearances during the feud between her husband Eddie Guerrero and Rey Mysterio, which had escalated when Eddie promised to reveal a secret concerning Mysterio's son, Dominick. Vickie was on the July 14 episode of SmackDown! with two of Eddie's three daughters to stop Eddie from revealing Mysterio's secret. Eddie promised not to reveal the secret should he lose to Mystersio at The Great American Bash, though that turned out to be another one of his character's trademark lies, as Eddie revealed that Dominick was really his biological son. Vickie later reappeared at SummerSlam to convince Eddie to put a stop to his war with Mysterio and not to go through with the "Custody of Dominick" ladder match that night. When that failed, she cost him the match by pushing over ladder he was on as he was about to win. On November 13, 2005, Eddie Guerrero died of heart failure in his Minneapolis hotel room and was found by his nephew Chavo. On-screen, this led to Rey Mysterio, Eddie's real-life friend, getting more screen time and higher profile matches, including defeating Kurt Angle and Randy Orton at WrestleMania 22 for the World Heavyweight Championship.
In 2006, approximately seven or eight months after Eddie's death, Vickie started appearing more prominently in more controversial storylines. She first asserted herself during a feud between Mysterio and Chavo Guerrero when Chavo accused Mysterio of being "nothing but a leech living off the blood of the Guerrero name" on the August 4 episode of SmackDown!. Subsequently, she acted as peacemaker between the two former friends until she seemingly inadvertently interfered in their match at SummerSlam in 2006, costing Mysterio the match. She then officially betrayed him by siding with Chavo and hitting Mysterio in the back with a steel chair on the following episode of SmackDown!, becoming a heel in the process.On the September 1 edition of SmackDown!, she declared herself Chavo's business manager and Mysterio an "insignificant chapter" in her past. At No Mercy, Chavo lost to Mysterio in a Falls Count Anywhere match. On October 20, Rey Mysterio lost an "I Quit" match against Chavo after interference from Vickie.On October 27, 2006, Chris Benoit became involved in the storyline. tried to figure out what Vickie was doing with Eddie's estate while also defending the WWE United States Championship in a rivalry with Chavo. At Survivor Series, Chavo kicked out of an attempted sharpshooter, causing Benoit to knock Vickie off the ring apron and on her head, causing her to begin to wear a neck brace and blame Benoit for "intentionally" hitting her. At the end of December, she interfered in a US Championship match between Chavo and Benoit, which caused Chavo to lose and Benoit to retain the title. As a result, Chavo shouted "If you wanted me to win the title, then stop getting me disqualified," before pushing Vickie over.