Purpose and Early Times
The Black Hand is an organisation withing the Brotherhood of Nod that acts as Nod's special operations unit, doing all of the Brotherhood's wet work. They are also responsible for guarding Nod important personel, capturing GDI head figures or scientists and guarding the religious ways of Nod. The Black Hand were confirmed to exist during the First Tiberium War, but Kane himself said that the Black Hand were some of the first to join the Brotherhood of Nod in "time immemorial". There are also suggestion that the Black Hand existed even before World War 1 and were the ones who actually caused it.
Cain killing his brother Abel. Within the Brotherhood, it is widely believed Cain is Kane.
First Tiberium War
During the First Tiberium War, they acted as Kane's pesonal guard and later the Brotherhood's special operations unit under General Gideon Ravenshaw. Their role didn't stop at being just a special elite unit, but they also formed Nod's religious police and a form of clerk keeping the Nod pseudo-religious identity pure.
General gideon Ravenshaw. The first known leader of the Black Hand. He was also head of the project ReGenesis, turning himself into a mutant supersoldier, but destroying his intelligence. He was eventually killed by Nick "Havoc" Parker.
Second Tiberium War
After the end of the First Tiberium War, the Black Hand vanished, just like most of the rest Nod groups. They made a re-appearance under Anton Slavik's command just before the Second Tiberium War, having gained enough power to match even Hassan's forces which were almost all the Nod forces on the eastern hemisphere. While it is unknown how Slavik became the leader of the Black Hand and how did they gain so much power in those desperate times prior to Tiberium War 2, it is known that their goal was to reveal that Kane was alive and reunite Nod under his command. Since Nod's reunification, they still acted as special operations unit, taking on the most essential missions.
General Anton Slavik. A Serb in nationality, he joined Nod when seeing his country's forces being crushed by the United Nations, as he had a hatred of the West and knew the Brotherhood was the only force strong enough to match them.
After the defeat of TW2 and during the CABAL uprising, they formed Nod's "shield" and joined the main army of the Brotherhood as their highly trained Elite Cadre units were the only match to CABAL's cyborgs.
An Elite Cadre soldier. These soldiers acted as guards for important areas and places but with CABAL's insurrection they were used in Nod's mainline force.
After the Crisis, internal strife raised within the Brotherhood and the Black Hand itself, which led to the assassination of Anton Slavik by Marcion's forces. Without anyone to lead the Black Hand and to hold the Brotherhood united, most commanders refused to accept Marcion as the true heir of Nod and formed their own Splinter Groups, while all Marcion loyal Black Hand followed their leader to self-exile in Australia. Marcion's ambitions and the Black Hand's inabillity to militarily match GDI's forces held the Brotherhood from maintaining ots place as a world superpower and leading to the Black Hand making unholy agreements with GDI to merely ensure their survival.
Impassionate and powerful, Marcion was one of the best religious preachers after the Second Tiberium War and commanded what was left of the Black Hand.
Third Tiberium War
Despite Marcion's claims about Kane, he gladly rejoined the Messiah and with his change of heart, the Black Hand again became the Brotherhood's core, leading to Nod's second reunification. During the Third Tiberium War, their ranks expanded even into the main Nod soldier ranks, while they were the Brotherhood's main asset for economic and military strength and continued their special operations.
The Black Hand flametroopers were a unit used by Nod mainline forces. Obedient, fearsome and supernaturally strong, they stroke fear into the hearts of GDI troops.
Fourth Tiberium War
After the Third Tiberium War they were almsot annihilated and were scatterred away from the rest of Nod. With Kane's unholy alliance with GDI, most of the Black Hand joined a new military figure, Gideon along with many other Nod commanders and swore to protect the Brotherhood's religious nature and to kill Kane while the minority remained adhered to the Black Hand's initial goal to protect Kane from any threat and co-operated with GDI alongside all other Kane loyalists. After the Fourth Tiberium War most of the surviving Black Hand ascended alongside Kane to an unknown future while the status of the rest remains unclear.
Gideon, although not officially the leader of the Black Hand, he commanded its biggest part alongside most of Nod during TW4. Although he was Kane's biggest rival for the command of Nod, many suggest he was a puppet rival put from Kane himself to throw dirt to the eyes of GDI.