Danielson defeated James Gibson for the ROH World Championship at Glory by Honor IV on September 15, 2005.
The rest of the year saw Danielson have successful title defenses even against wrestlers from other companies, such as Pro Wrestling Noah star Naomichi Marufuji at Final Battle on December 17.

At the beginning of 2006, Chris Hero, a representative from Combat Zone Wrestling (CZW), invaded ROH and targeted Danielson—the two exchanged words over the internet before having a match together, with nearly the entire roster of both companies embarking on an interpromotional feud.
Danielson became personally invested in this feud and invaded CZW himself, which led to him having physical altercations with a number of CZW wrestlers.
Hero intensified the rivalry, leading to the two wrestling at ROH's Hell Freezes Over event on January 14, where Danielson successfully defended the ROH World Championship.
On July 15 at Death Before Dishonor IV, he soon filled the vacant slot on ROH's five-man team which participated in one of CZW's more popular attractions, a steel cage match called the Cage of Death, a ten-man tag team match in which a man from each team starts in the cage and a random wrestler enters periodically thereafter.
During the match, Danielson turned on his team by assaulting his rival Samoa Joe before leaving the match and effectively abandoning his involvement in the animosity between the two promotions.
As the interpromotional hostility with CZW heightened, Danielson also defended against challengers from the rival company, who had signed an open contract for any CZW wrestler willing to challenge for the ROH World Championship.
Former champion Samoa Joe also challenged Danielson at Fight of the Century on August 5, but their match ended in a 60-minute draw.

While having the ROH World Championship, ROH faced the issue of having another title with seemingly equal value, the ROH Pure Championship.
Danielson and the ROH Pure Champion Nigel McGuinness had a match to unify the titles.
They met at April 29 in a match fought under pure wrestling rules and McGuinness left Danielson outside the ring after a chair shot to win by countout—this was enough to retain the Pure title, but not to win Danielson's World Championship.
They had another unification match in McGuinness's native England; ROH decided that there had to be a winner, with a title changing hands by countout and disqualification and a draw forcing a restart.
Danielson won the match on August 12 and retired the Pure title as its last champion (the title would be reinstated in 2020).
During a match with Colt Cabana on August 26, Danielson suffered a real injury when he separated his shoulder, tearing two tendons in it and he tore another tendon in his chest.
Danielson returned at Glory by Honor V: Night 2 on September 16 and was challenged by Kenta, a guest competitor from NOAH, due to the two company's talent exchange agreement—Danielson again retained his championship.
At Final Battle on December 23, Danielson's fifteen-month title reign finally ended after he lost to Homicide at his 39th defense and he subsequently took time off from wrestling in order to heal his shoulder.
Danielson defeated James Gibson for the ROH World Championship at Glory by Honor IV on September 15, 2005. The rest of the year saw Danielson have successful title defenses even against wrestlers from other companies, such as Pro Wrestling Noah star Naomichi Marufuji at Final Battle on December 17.
At the beginning of 2006, Chris Hero, a representative from Combat Zone Wrestling (CZW), invaded ROH and targeted Danielson—the two exchanged words over the internet before having a match together, with nearly the entire roster of both companies embarking on an interpromotional feud. Danielson became personally invested in this feud and invaded CZW himself, which led to him having physical altercations with a number of CZW wrestlers. Hero intensified the rivalry, leading to the two wrestling at ROH's Hell Freezes Over event on January 14, where Danielson successfully defended the ROH World Championship. On July 15 at Death Before Dishonor IV, he soon filled the vacant slot on ROH's five-man team which participated in one of CZW's more popular attractions, a steel cage match called the Cage of Death, a ten-man tag team match in which a man from each team starts in the cage and a random wrestler enters periodically thereafter. During the match, Danielson turned on his team by assaulting his rival Samoa Joe before leaving the match and effectively abandoning his involvement in the animosity between the two promotions. As the interpromotional hostility with CZW heightened, Danielson also defended against challengers from the rival company, who had signed an open contract for any CZW wrestler willing to challenge for the ROH World Championship. Former champion Samoa Joe also challenged Danielson at Fight of the Century on August 5, but their match ended in a 60-minute draw.
While having the ROH World Championship, ROH faced the issue of having another title with seemingly equal value, the ROH Pure Championship. Danielson and the ROH Pure Champion Nigel McGuinness had a match to unify the titles. They met at April 29 in a match fought under pure wrestling rules and McGuinness left Danielson outside the ring after a chair shot to win by countout—this was enough to retain the Pure title, but not to win Danielson's World Championship. They had another unification match in McGuinness's native England; ROH decided that there had to be a winner, with a title changing hands by countout and disqualification and a draw forcing a restart. Danielson won the match on August 12 and retired the Pure title as its last champion (the title would be reinstated in 2020). During a match with Colt Cabana on August 26, Danielson suffered a real injury when he separated his shoulder, tearing two tendons in it and he tore another tendon in his chest. Danielson returned at Glory by Honor V: Night 2 on September 16 and was challenged by Kenta, a guest competitor from NOAH, due to the two company's talent exchange agreement—Danielson again retained his championship. At Final Battle on December 23, Danielson's fifteen-month title reign finally ended after he lost to Homicide at his 39th defense and he subsequently took time off from wrestling in order to heal his shoulder.
Daniel Bryan