As 2005 began, Triple H realized the possibility of Batista, much like Randy Orton the year before, becoming a threat to his World Heavyweight Championship. Triple H suggested that Dave not enter the
Royal Rumble, claiming that it would be selfish of him to do so, and to simply focus on Triple H retaining the title. Dave entered anyway and went on to win the Royal Rumble, last eliminating
John Cena, earning the right to participate in the main event of
WrestleMania 21 against the World Champion of his choice.
In an attempt to persuade Batista to challenge
WWE Champion John "Bradshaw" Layfield rather than him, Triple H concocted a scheme to have Batista
run over in a
limousine resembling the one used by Layfield. Initially, Dave did not want help from Evolution and wanted to confront JBL by himself. Triple H insisted that Evolution stick together and accompanied Dave anyway, saving him from the oncoming vehicle. Batista became aware of the plot while sneakily eavesdropping on fellow Evolution members and signed a
contract guaranteeing him a match with World Champion Triple H at WrestleMania 21, thus leaving Evolution and officially turning face for the first time in WWE. Batista initially pretended that he would sign with
SmackDown!, giving Triple H and Flair the "thumbs up," but turned it into a "thumbs down" before attacking the pair. He emphasized his departure by
powerbombing Triple H through the table used for the contract signing.
Batista went on to win the World Heavyweight Championship on
April 3 2005 at WrestleMania 21. Since this event, he has used the infamous "thumbs up, thumbs down" gesture before he performs the Batista Bomb on his opponent. Batista once again faced Triple H for the World Heavyweight Championship at
Backlash. He retained the title but continued to
feud with Triple H. Along the way, he even helped commentator
Jim Ross gain an upset victory over Triple H on
RAW. After Batista retained his title against
Edge, he was betrayed by Ric Flair, who helped Triple H viciously attack the champion as Triple H challenged Batista to
Hell in a Cell at
Vengeance 2005. Batista survived the
pedigree and won the match at Vengeance, retaining his title yet again. With this win, Batista became the first wrestler to pin Triple H in a
Hell in a Cell match.
On
June 30 2005 Batista was revealed as the last pick in the
2005 WWE Draft Lottery, making a surprise appearance while John "Bradshaw" Layfield was celebrating his victory in a six-man elimination match to win the new
SmackDown! Championship. JBL and Batista faced off at the Great American Bash on
July 24 2005 where JBL defeated Batista by DQ after the referee saw Batista use a steel chair. They had a rematch at
SummerSlam on
August 21 in a No-Holds-Barred match in which Batista pinned JBL following a powerbomb on the steel steps. The feud culminated in a match between the two on the first episode of
SmackDown! broadcast after the show moved to Friday nights, with Batista retaining the title in JBL's signature bull rope match.
Soon after retaining the title in a feud with
Eddie Guerrero, WWE.com reported that Batista suffered a muscle tear in his back at the taping for the
November 11 2005 edition of
SmackDown! due to a double chokeslam from
Big Show and
Kane. Plans had been made for Batista to defend the title in a triple threat match with Eddie Guerrero and Randy Orton on the
November 18 episode, but the match did not take place due to the unexpected death of Eddie Guerrero on
November 13 2005, the date of the taping. Batista paid homage to Eddie Guerrero during the
SmackDown! and
RAW tribute shows dedicated to Guerrero's memory.
Batista led Team
SmackDown! against Team
RAW in an inter-brand feud before
2005's Survivor Series. The feud saw the Big Show and Kane chokeslamming Batista several more times in the weeks leading up to Survivor Series in an on-camera explanation for Batista's injury. Batista ultimately helped his team win the Survivor Series main event. After Batista saved
Rey Mysterio from a double team attack by
RAW's reigning
World Tag Team Champions, Big Show and Kane, it was announced that Mysterio would team with Batista to face Big Show and Kane at
Armageddon 2005, a
SmackDown! exclusive pay-per-view.
On the
December 16 edition of
SmackDown!, Batista and Mysterio defeated
WWE Tag Team Champions MNM to become champions in a match they dedicated to Eddie Guerrero, and the clash with the Big Show and Kane at Armageddon turned into a Champions vs. Champions encounter. Batista and Mysterio lost to Kane and Big Show at Armageddon when Kane pinned Mysterio after a chokeslam, and two weeks later on
SmackDown!, MNM defeated Batista and Mysterio after help from the returning
Mark Henry to regain the WWE Tag Team Championships. During the interference, Henry attacked Batista, and performed his
World's Strongest Slam.The teams met again in a cage match that Henry also became involved in, and Batista and Rey were defeated again.