Grief-stricken, Mikael decided to search for a way to protect his family from the werewolves. Though their family friend Ayana refused to help him in fear of upsetting the balance of nature, Mikael soon found another witch who would help him – his wife, Esther. Somehow, they were able to learn of the immortality spell created by Qetsiyah a thousand years previously, and adapted the spell in order to give their children abilities of superhuman strength, speed, agility and healing that would be even stronger than those of the werewolves. Esther drew on mystic symbols in order to fuel her spell; she called upon the Sun for life, and the white oak tree, long known for being one of the earth's eternal objects, for immortality, so that she and Mikael would never again have to suffer the grief of losing a child.

In order to complete the ritual, Mikael had his children drink wine laced with the blood of Tatia, a Petrova doppelgänger and distant descendant of the world's first immortal woman, Amara before he then thrust his sword through their chests. They awoke in transition, and on their father's orders, drank Human blood from a village girl in order to complete their transformation into the Original vampires. Unfortunately for them, there were consequences for this transformation, and Nature sought to try to restore the balance they upset by giving them a weakness for every new strength they had gained.

The sun that gave them life burned them, their thirst for human blood was insatiable, and their neighbors could lose their homes to them by not inviting them inside. Vervain flowers, which grew at the base of the white oak tree, burned them and protected against compulsion. Finally, the White Oak Tree, which gave them immortality, was also the one substance on earth that could actually destroy them for good. In the end, they burned the tree down to ensure their survival, though the ashes were saved to later be used against them. When Klaus made his first kill after being turned into a vampire, it triggered his werewolf gene, which ultimately revealed the truth of his parentage to his family - Klaus was not Mikael's son but was instead the son of the chief of their village's werewolf clan, with whom Esther had an affair.

Once Mikael learned of Esther's infidelity and realized that her lover's pack were the werewolves who had killed Henrik, Mikael hunted down and killed Klaus' father and his entire family, igniting a war between Vampires and werewolves that still exists to this day. Soon after the Mikaelsons were turned into vampires and learned of Klaus' werewolf heritage, Esther was obligated to curse Klaus in order to make his werewolf nature dormant so that he would not upset nature further by possessing so much power. However, Klaus felt betrayed by this punishment, and in retaliation, Klaus murdered his mother and framed Mikael for the act.