He had inherited the Emperor's coldest logic. When he entered the world of mortals and received everyone's care, he did not know how to return those feelings. He knew he had been born as a powerful weapon. While proud of his exceptional abilities, he was also confused by his inability to understand mortal emotions.
If Perturabo had not had such a relatively happy family, he might truly have become the Lord of Iron, with cold armor and a cold heart embodying the creed of iron within and without.
The love he received from mortals had left a crack in his solid metal. It had neither upheld the creed of iron within and without, nor created another man like Roboute Guilliman.
Under the influence of this contradiction, Perturabo became more and more twisted as he lived on.
Although his opinion of Dorn was especially terrible, and he had to humiliate Dorn viciously to feel any pleasure, in the stillness of the night he would also remember that many of the tactics he used had been taught to him by Dorn. In his confusion, he would ponder how his relationship with Dorn had become so terrible.
He hated his other brothers and treated them with disdain, yet privately made unique gifts for them in his tiny bedroom. Unfortunately, when the rebellion broke out, he never had the chance to give those gifts away.
Perturabo was proud. Beneath pride as towering as Mount Everest, there was a small measure of tenderness. Yet that tenderness was obscured by his twisted personality and ignored amid the indifference of his other brothers, causing this hard-working fellow to lose all faith and patience in everything.
This twisted man had his soul wounded by Fulgrim, yet while severely injured, as he watched Fulgrim ascend to daemonhood and fall