Arrival on Medusa
He awoke after his pod crashed on Medusa, in the centre of a colossal mountain of black rock and ice. He left the pod and inspected his surroundings: he discovered an "X" mark on his pod and that the chamber was too precise to be a natural formation. Exploring further, he discovered runes and electro-conductive stalagmites all around the chamber. His inspections awakened an imprisoned colossal biomechanical worm-like creature, which attacked him and escaped, ignoring his attacks. He followed its path of destruction and swore he would destroy the beast he had unwittingly released. When he reached the surface, he saw other men in the distance but wouldn't reveal himself to them, keeping his recent oath in mind.
Ferrus would not join these tribes, as many of his brothers did. Instead, he sought out physical challenges to make himself stronger and more resilient. These tests ended with his battle against the Great Silver Wyrm Asirnoth, a metallic beast impervious to harm; Ferrus had to drown it in magma to kill it. The melted flesh of the wyrm fused to Ferrus's flesh, giving him the true metal hands his Legion would take its name from[Needs Citation].
Ferrus returned to the tribes and lectured them on technology. The clans advanced at a stunning pace and Medusa prospered, but Ferrus took care to leave the inter-clan rivalry and fighting by never taking sides, as he saw the competition between them as healthy and good[Needs Citation].
The Emperor eventually came to Medusa and Ferrus Manus tested himself on him in a cataclysmic battle that is said to have lain waste to entire mountains. Finally having found someone equal, Ferrus accepted the Emperor as his master and took command of a legion of Space Marines [Needs Citation].
Thousands of planets would fall to the remorseless Iron Hands under Ferrus's leadership. Each weak link in humanity was to be purged if mankind was to grow stronger. Scholars spoke of the wave of piety and faith that spread before the Iron Hands, with many planets suddenly motivated to look into themselves when they heard that the Iron Hands were approaching[Needs Citation].
Once swayed himself to the side of the Warmaster, Fulgrim approached Ferrus Manus before the heresy and tried to lure him to join Chaos. Ferrus Manus was so enraged at this proposal that he attacked Fulgrim. A short duel took place, where Ferrus destroyed Fulgrim's sword Fireblade, the same weapon Ferrus had given to him many years before. Fulgrim escaped after rendering Ferrus unconscious, leaving him alive but taking with him the massive thunder hammer he himself had crafted for his brother.
The Iron Hands was one of the loyal legions the Emperor called to Isstvan V. Given the large distance, Ferrus Manus took the Legion's fastest ships and departed only with his veterans. Most of them died in this battle, when following the loss of their primarch they were struck down by the traitor legions, caught between the hammer of the Emperor's Children and upon the Anvil of the four support legions of the second wave. 
Fulgrim personally killed Ferrus during the battle at Isstvan V, using the daemon weapon he acquired fighting the Laer to strike his head from his shoulders in one fell swoop. Fulgrim was distraught with grief that his closest brother was dead by his own hand, eventually giving into the whispers of Chaos to ease his pain, which ripped apart his mind and soul, overtaking his body and pushing him into the deepest corners of his mind. It turned him into a Daemon Prince and he brought Ferrus's mutilated head before Horus. 
Ferrus Manus is Latin for "Iron Hand."
|I - Lion El'Jonson · II - Unknown · III - Fulgrim · IV - Perturabo · V - Jaghatai Khan · VI - Leman Russ · VII - Rogal Dorn · VIII - Konrad Curze · IX - Sanguinius · X - Ferrus Manus · XI - Unknown · XII - Angron · XIII - Roboute Guilliman · XIV - Mortarion · XV - Magnus · XVI - Horus · XVII - Lorgar · XVIII - Vulkan · XIX - Corvus Corax · XX - Alpharius Omegon|
- 1: Iron Hands (Novel) by Jonathan Green
- 2: Fulgrim (Novel) by Graham McNeill
- 3: The First Heretic (Novel) by Aaron Dembski-Bowden
- 4: Angel Exterminatus (Novel) by Graham McNeill Book 2 As Above so Below - Theogonies II