Anastasia IV is a new unit introduced in Metal Slug Attack.
The fourth priestess of an unknown sect, Anastasia IV and her predecessors were guarding a hidden treasure that Ptolemaios was interested in. After many gruelling battles, she successfully negotiated with Ptolemaios and the two became allies.
She uses the many artefacts that her predecessors used to defend the hidden treasure. Very few outsiders are aware of the sect. Due to her position, she trusts very few people. Some of the people that she fully trusts is the Master Believer and Beecham.
While she does not make an appearance in any Extra Ops yet, she is mentioned in "United Front the 9th", where she sends Beecham to find out what Mira is hiding.
Her mother, Anastasia III, died of unknown causes, prompting Anastasia IV to become the new leader of her sect. However, she was still young, so the Master Believer assisted her until she was old enough.
By the time she is old enough, the sect is having trouble against the Rebel-backed Arabian Army. She considers her options, and decides to call the Ptolemaic Army to help them, since they are only allied in name. The Master Believer accepts her request and sends a courier to reach them. The courier manages to reach them, but dies upon arrival because he battled the Arabians while leaving.
Mira arrives and she negotiates with Anastasia IV - she's shocked upon hearing that the courier died. Mira tells her that she is willing to help if they give her the "core". She agrees to, and when Mira leaves, she's upset that they had nothing to barter with. They battle more Arabians and make their way to the ruins where the core is held. On the way, she falls unconscious due to the power of the staff. In her mind, she has a vision of the Red Goblin being cut down by Mira, and when she wakes up, tells the Master Believer what she saw; Ptolemaios cannot be trusted, and they must gain strength while watching them.
Defeating various alien machinery guarding the ruins, they eventually arrive and encounter an alien, who puts Anastasia into comatose-like state and shows her another vision, one of war. Upon waking up, the alien challenges her to a battle of strength, which she prevails and is given the core by the alien. She sends a believer to deliver it and to watch them. The Master Believer gives her his input on the situation, and all she can hope for is that the suspicious believers will understand her intentions one day.
- She was named after Anastasia, the Empress consort of Constantine IV of the Byzantine Empire.
- She appears to be based on the goddess Palutena from the Kid Icarus series by Nintendo, despite being entirely a mortal human.