Discard Circling Vultures from your hand using its static ability.
Because Circling Vultures is a Lhurgoyf due to Ashes of the Fallen, Disa the Restless's first ability triggers, putting Circling Vultures from your graveyard onto the battlefield.
Activate Umbral Collar Zealot by sacrificing Circling Vultures.
When Circling Vultures dies, Enduring Renewal triggers, returning Circling Vultures from your graveyard to the battlefield.
Resolve the Umbral Collar Zealot ability
Repeat.
This clever loop turns your graveyard into an infinite engine by transforming a humble bird into an honorary Lhurgoyf with Ashes of the Fallen. When you discard Circling Vultures from your hand, Disa the Restless catches it on the way to the graveyard and immediately drops it back onto the battlefield. From there, you can sacrifice it to Umbral Collar Zealot, which triggers Enduring Renewal to bounce the Vultures right back to your hand so you can repeat the whole cycle.