Promise was created by Fabian Nicieza.
Tim Drake comes across Promise in Moscow as she attempts to attack a Russian dignitary by the name of Viktor Mikalek as he is trying to discover his connections to The Calculator. Promise uses nonlethal ammunition and demonstrates a advanced level of athleticism. Red Star eventually breaks up the attack, leaving Drake to dawn his Red Robin attire, finding her later. Promise informs Red Robin that Mikalek led to her brother's death, and his uranium mines destroyed her home, and many objects her family had in possession for years. While in the Unternet universe, she has been fighting villains for 15 years. Trying to expose Calculator and his villain followers. After she helped Tim Drake in that realm, Promise was shot by Deathstroke and returned to the real world.
A couple months later, Tim learns from Scarab about a Tournament of Assassins so he begins digging around to find any truth in this. Apparently, one of Scarab's scouts tried to assassinate Lucius Fox as an initiation to participate in this tournament but Tim prevented it. Eventually, Moneyspider comes up with something on the Unternet. Lonnie finds out that somebody has put a hit on Viktor Mikalek. Tim decides to head to Moscow and stand guard over Mikalek's hospital room because Mikalek is healing from his encounter with Tim in the Unternet. Tim figures Promise will probably be the one who will take the assignment since she has her personal vendetta against Mikalek.
During his routine search of Mikalek's room, Tim spots a sniper rifle from an adjacent building. Tim throws a batarang to knock the rifle out of its place then he grapples to the building. Tim crashes through a window and discovers the rifle he hit but he couldn't find the sniper. Suddenly, a giant Russian in a mask, comes charging through a wall and attacks Tim. Fortunately, Promise showed up and shot the Russian with a spray of rubber bullets. Unbeknownst to Tim, Promise was the one who arranged for this event to happen because she has own plans in store for Red Robin.
When Tim searched the Russian for clues, Promise unleashes her shadow casting abilities to subdue Tim. Tim wakes up without his mask and finds himself chained to the floor with Promise standing in front of him. She kneels down and tells Tim that she had anticipated on him going to Moscow in order to protect Mikalek because she would be the chief suspect in Mikalek's murder plus she was the one who put the contract out on Mikalek in the hopes of killing two birds with one stone.
After this stirring revelation, a cloaked figure who turns out to be Scarab approaches Tim. Promise informs Tim that Maat is her half sister and they belong to a secret order called the Daughters of Acheron. They have different mothers but the same father. Acheron is quite possibly Hades in human form and he has given his daughters the ability to manipulate shadows.
Maat begins to undress and she tells Tim that she is the half-sister of Ra's al Ghul. Maat also confesses that she has been impressed by Tim's ingenuity thus far and just before Promise kills him, Maat wants to have Tim's baby. Fortunately, Cassandra Cain has been following Tim's movements ever since the Assassin's Tournament was mentioned. Cassandra makes short work of Promise and Tim knocks Maat out.