Swiftcast materia is a 
Support Materia in Final Fantasy VII Rebirth. It can be linked with 
Magic Materia to reduce the cast time of its spells. At maximum level the linked spell is cast instantly, but even at lower levels, reduction in cast times can greatly increase the value of certain spells.
Obtained
Swiftcast materia is bought from Chadley's Meridian Ocean Materia Development for 5 data points. The player needs to complete his protorelic quest and fight the boss at the end of this questline to be able to access Chadley's final Materia Development.
Stats
| Level | AP required | Effect |
|---|---|---|
| 1 | 0 | 50% reduction in cast time |
| 2 | 1,000 | 60% reduction in cast time |
| 3 | 2,000 | 70% reduction in cast time |
| 4 | 6,000 | 80% reduction in cast time |
| 5 | 18,000 | 100% reduction in cast time |
Use
Swiftcast materia reduces the cast time of spells from its linked materia. The extent of the shortening in cast time increases as swiftcast levels up, though it demands large amounts of AP to reach its highest level, which eliminates cast times altogether.
Swiftcast is best used for higher-tier spells that have long cast times. Pairing it with Healing Materia for 
Curaga, or with Revival Materia for Arise, or Reraise Materia for Reraise, can in many battles come in clutch, allowing the user to cast the spells more safely in otherwise dire scenarios. On the flip side, it can be paired with Fire Materia for Firaga (or one of its peers), or especially with Comet Materia due to its lengthy cast times for Comet and Cometeor.
In most cases, the player will more than likely use the materia for defensive spells. However, there are cases where a player may pair two copies of an offensive materia, where one is paired with swiftcast and another with Magnify Materia, to cast a higher-tier offensive spell that hits multiple enemies much quicker. Another good combination is pairing another copy of magic materia with the same spells to Synergy Materia to cast follow-up spells faster. There are similar support materia pairings that can also take advantage of swiftcast for higher-tier spells.