Allows you to absorb an ally's limit gauge to fill your own with Limit Siphon.
Description
Limit Siphon materia is a 
Command Materia in Final Fantasy VII Rebirth. Its ability, Limit Siphon, will take the current limit gauge from another party member and add it to the user's limit gauge. The ability costs one ATB charge.
Obtained[]
Limit Siphon materia is bought from Chadley's Materia Development in the Gongaga Region for 40 data points.
Use[]
Limit Siphon takes the limit gauge from another party member to fill the user's. This can be used to unleash limit breaks more frequently, allowing them to become a major source of damage rather than simply a weapon in desperation. This is more effective at higher limit levels, as provided by synergy abilities.
Limit Siphon can also be used in tandem with 
Limit Support Materia and/or a relevant accessory 
Transference Module, Spectral Cogwheel, Limit Booster, or Gotterdammerung to boost limit gauges faster so that one party member can use their limit breaks more often. Alternatively, Genji Gloves can be used to allow the limit breaks in question to break the damage limit.
When Expeditionary Medal is equipped on either party member, they will start at limit level 2, and when if Enhanced Expeditionary Medal, they will start at limit level 3. Giving Limit Siphon to them also allows them to use higher-level limit breaks more frequently.
Aerith has unique supportive limit breaks, such as Planet's Protection, that can boost the party in many ways, while Rising Fury can fill all ally limit gauges at once. The player can equip Limit Siphon to her, steal an ally's limit gauge, use Rising Fury to fill both allies' limit gauges, use one of the allies' limit breaks while again siphoning the other, and use Rising Fury again, letting the player use back-to-back limit breaks. Tifa, on the other hand, has limit breaks that can prove a major source of damage, and if using Limit Siphon to achieve this more frequently either from using Limit Siphon herself or from Aerith's Rising Fury, she can be devastating to opponents.