Transition magic (転移魔法 Ten'i mahō, localized as teleportation magic) is an extremely powerful and rare magic that was used by the Ten Sages and previously also by Rachel Alucard. It is known as an extremely advanced magic spell.
To use this type of transition, the magician has to clearly imagine its destination point. The complexity depends on the weight of transitioned objects and distance of transition, though it can be compensated if the transition is done by several magicians.
This magic possess a risk of its own, which rises along with complexity of the barriers one must pass through, as well as with the size and number of objects/people/space being transported. The more complex a barrier is, the further the user has to twist the fabric of time and space, which might result in ending up in a random place, or even being crushed by dimensional tides. That is why fixing up coordinates is the most important, as well as the most difficult part, of the spell.
Transition magic itself has been seen from BlazBlue: Calamity Trigger onwards and has been seen as Rachel's staple technique, often using it to traverse the BlazBlue world, particularly from the Moonlight Castle to the 13th Hierarchical City "Kagutsuchi". Rachel has actually been in possession of the ability for a large number of years, with its first chronological usage being in BlazBlue: Phase Shift 1 when she teleports herself and Tomonori into Moonlight Castle from the Magic City Ishana. After Rachel sent Ragna the Bloodedge back 100 years in time via transition (in conjunction with a nearby Kiln), she lost the ability to use transition magic.
Rachel was known to be especially skillful at utilizing this type of magic. While Konoe was able to transport an additional person or few with her at a time, Rachel was capable of moving a whole troop or a squadron. She was even capable of directly teleporting through multiple layers of barriers, reaching to places that were deemed impossible to enter through transition.