Prior to the events of BlazBlue, humanity was on the verge of extinction from a creature called the "Black Beast." The world was saved by six heroes who wielded magic. They helped humanity create "Armagus", a fusion of magic and science, to defeat the Black Beast. This event would be later known as the First War of Magic. After the war, the Novus Orbis Librarium (the Library or NOL for short) was created to govern the world with the use of Ars Magus. A great deal of dissent was caused by the Library, partly due to Armagus' use in nearly every facet of society, and the widening socioeconomic gap between those who could and couldn't use Armagus. This dissent would eventually form years later into the Second War of Magic or also known as the Ikaruga Civil War, when the city of Ikaruga openly rebelled against the NOL. Upon winning the war, the NOL imposed a harsher rule on the world, punishing any rebellion against the NOL with death. In December A.D. 2199, several years after the Second War of Magic, a branch of the NOL was utterly destroyed by an SS-class rebel named "Ragna" also known as the "Grim Reaper", in an attempt to destroy the Librarium. The NOL, hoping to stop him, immediately announced the largest bounty ever, available to anyone who could capture him. Interestingly, Ragna possesses a powerful form of Armagus known as the "Azure Grimoire". This led the NOL, as well as the other fighters, to hunt Ragna not just for his bounty, but also his Azure Grimoire.

The game is set after the events of BlazBlue: Calamity Trigger. A few days have passed since the reported raid by Ragna the Bloodedge, The 13th Hierarchical City "Kagutsuchi" forgets to celebrate New Years, as his alleged involvement in the "Mysterious Bombing" and "Huge Pentacle Sightings" becomes the talk of the town. With the NOL offering no official explanation, the citizens voice their own theories, exaggerating and spreading rumors like wildfire. Completely indifferent to the state of the city, Ragna grips his massive sword and quietly bides his time—waiting for the chance to achieve his true objective, and then, the enormous "power" that has ensnared Ragna begins to activate.

-Gold Break Burst: Duration decreased, less invincibility, easier to bait and punish.
-Green Break burst: Hitting the opponent with the burst, or if it is blocked, will give a 25% heat boost to the meter.
-Knockback: Air guarding a ground attack now has increased knockback making it easier to gain distance.
-Barrier Guard: More knockback on moves with a higher attack level.
-Instant Barrier guard: Even more knockback, allowing for an easier get away.

Penambahan Relius Clover dan cerita baru karakter karakter yang tak sempat di tampilkan saat Calamity Trigger

Update besar-besaran oleh Arcsys, Sprite digambar ulang, Music baru, dan banyak hal baru lain nya