Overcast (a Touhou LW original) refers to the weather when the sky is entirely covered by clouds. This is the temperament of Sakuya, who blocks the sun's light as the servant of a vampire. This Sakuya's temperament was artificially augmented by science since her original temperament lost its magic. This temperament is specialized to solely resist Moon Essence.

Sakuya Izayoi's sealed ability. It was most likely sealed away due to the incident, and it hasn't fully recovered since. The reason for this is still unclear and requires further investigation. Sakuya Izayoi's Specialized Military Outfit: The design and manufacture of this outfit were largely based on the work of Patchouli Knowledge's Knowledge Institute and the support unit "Koakuma." All of the specialized military outfits are equipped with barrier chaff. Cold Knives & Knife Stockers: Sakuya's main weapons that were designed with Patchouli's vast knowledge. The knives are kept at an extremely cool temperature by applying the principles of ice magic. These cold knives are devoid of all internal vibrations, which makes them especially suited for throwing. There are many variations of knives, including Patchouli's favorite paper knives and the knives Sakuya usually uses. The Knife Stockers also act as vernier thrusters to provide a significant boost to Sakuya's speed. Artificial Qigong Assistance: Equipment based on Meiling's ability that have been designed to support Sakuya's physical skills. A network on the inner layer of the outfit artificially replicates Meiling's ability to control the flow of qi within one's own body. This supports Sakuya's muscles and can even provide instantaneous bursts of strength on par with the strength she used to possess. Various Support Modules: Hobgoblin, Tupai, and Fairy_Maid are the three types of support modules. Sakuya's movements are supported by short-running programs that replicate each of these creatures' characteristics and powers. Dual Noble Vampire Units: Central systems that hover near Sakuya's head and support her thoughts. One unit replicates the mind of Remilia, the other replicates Flandre's, and they both cooperate with Sakuya's own mind to almost instantaneously provide the optimal solution to any problem. The Remilia Unit mainly provides support by foreseeing how the battle will progress, while the Flandre Unit discerns the enemies' weaknesses.