Jaffa leader who submitted to the Ori as his new gods once their followers infiltrated the Milky Way Galaxy to spread Origin. Much like the Sodan, he believed Origin to be an organized religion seeking what Jaffa everywhere have always sought to achieve -- ascension. To Teal'c he was a warrior without honor.
Arkad and Teal'c had once engaged in battle with one another as opposing First Primes. Arkad always admired Teal'c, even after he was responsible for annihilating Arkad's parents and sister on the planet Co'rak. After the embarrassing defeat, Arkad had Teal'c's mother killed in response.
After the Ori managed to get a foothold in the Milky Way, it is believed Arkad came to an agreement with the Ori armies, allowing him to build support for himself as a new leader and, at the same time, deliver the Jaffa people into the hands of the Ori. Soon, he commanded the greatest army of Jaffa forces, superior tenfold to the largest army ever amassed by a Goa'uld.
Arkad traveled to Earth to ensure General Landry and the rest of Stargate Command that he was not responsible for the attack on a Jaffa summit at Dar Eshkalon. Meanwhile, he worked with the fanatical Illac Renin to continue to gather naquadah for an all-out attack on Earth.
Despite Landry's objections, Teal'c journeyed to Arkad's planet on his own to defeat the leader, who he was convinced destroyed the Dar Eshkalon summit. Shortly before Teal'c murdered him, Arkad admitted that he did indeed kill Teal'c's mother.
Talion - Arkad journeys to Earth to buy time for his ongoing plans to place Earth in the hands of the Ori.
Family Ties - Even following his death, Arkad's plans to defeat Earth are still in swing with the Illac Renin, who are gathering naquadah to destroy the planet.