At last the brand was removed and Uriel gasped. The pain was still there, raw, hot and intense, but compared to the agony of the continued burning, it was as though his upper arm were bathed in cool water.

A pair of robed chirurgeons stepped from the darkness behind him and the pain was replaced by a cool, clear sensation of relief as counterseptic was applied to the wound and burn gauze bound to his shoulder.

'That is the first lesson,' said Leodegarius, handing the brand back to the servitor. 'When we begin, you are to speak only when I permit you to speak. Do you understand?'

'Yes,' said Uriel, nodding, 'I understand.'

'Then you are ready for the first ordeal,' said Leodegarius, 'the Ordeal of Inquisition.'

'What are you going to ask me?'

'Ask?' said the Grey Knight. 'I am not going to ask you anything.'

Concentric circles were inscribed on the floor around Uriel and Leodegarius, cut by hooded servitors with acetylene torches for arms, and the grooves filled with bubbling lines of molten silver dispensed from golden urns upon their backs. Strange sigils that were incomprehensible to Uriel were cut in the space between the two circles, which were likewise filled with silver.

Steam billowed from the design as the servitors finished the last of the silver sigils.

'The Ordeal of Inquisition,' said Leodegarius, 'is as old as my order. My mind's eye will see into every darkened corner of your soul. I will know your every thought. You will be able to hide nothing from me. Understand that and you may save yourself a great deal of pain. If you have evil within you, confess it and your death will be swift. Deny it, and if I find any trace of corruption, your death will be agonising and long.'

'I have nothing to confess,' said Uriel. 'I am not corrupt.'

Leodegarius nodded, as though playing out a familiar drama. 'We shall see.'

At last the design on the floor was complete, and the servitors vanished into the darkness, leaving Uriel and Leodegarius alone. As the servitors withdrew, seven other acolytes approached, each carrying a torch, their hoods drawn back. The firelight danced on their faces,, and the withered horror of their hairless heads made Uriel long for the darkness again.

Their faces were those of corpses found in the desert, drawn and desiccated as though drained of all vitality and animation. Their eyes had been burned from their sockets, although whether by deliberate artifice or by nightmarish sights, Uriel could not say.

As a Space Marine in the service of the Emperor, Uriel had seen his share of terrors: ancient star gods, the face of the Great Devourer and the abode of daemons, but to see these pitiful beings was to know that there were more terrible things still in the galaxy.

The dreadful acolytes took up positions around them, forming a protective circle, and began to chant with a barely audible, static-like screech. Their low voices set up an atonal wall of sound without rhythm and Uriel felt the same deadening of the senses that he had felt when hooded.

'The Null-Servitors create a barrier of psychic feedback,' explained Leodegarius. 'Together with the lines of power inscribed in the floor, it will prevent any corruption from leaving this circle should I falter in my inquisition of your body and soul.'

'I understand the precaution,' said Uriel, 'but I keep telling you it is unnecessary.'

'Be silent,' instructed Leodegarius, stepping forward and placing his hands on either side of Uriel's face. 'The Ordeal of Inquisition has begun.'

The metal of the gauntlets was cold and Uriel felt their chill spread down through his skin, into the muscles of his face and past the bone of his skull. Cold, questing fingers prised open the lid of his mind and delved inside.

Uriel's immediate inclination was to resist and the mental barriers of his will began to erect in response to the invasion. He looked into Leodegarius's icy blue eyes and the world seemed to contract until all he could see were those glacial orbs, as though crackling lines of power that could never be broken connected them.

Uriel felt his entire body grow numb as the Grey Knight's psychic essence forced its way through his defences and into his thoughts.

'Why do you resist?' asked Leodegarius, the implacable force of his mind pressing on Uriel's thoughts. 'Do you have something to hide after all?'

Uriel tried to reply, but his tongue would not obey him. He tried to lower his defences and allow his interrogator access to his thoughts, but the natural reaction of a human mind is to protect its secrets and internal workings.

Yet even as the defensive architecture of his brain buckled under the strain of resistance, Uriel knew that such a struggle would be futile in the face of the Grey Knight's power. With that realisation came the will to allow another being access to the hidden fortress of his mind: the guarded place where he kept his doubts, his fears, his hopes and his ambitions.

Everything that made him Uriel Ventris would be laid bare for Leodegarius to see, to know and to understand. Every virtue and every vice was open to scrutiny and if Uriel were found wanting in any regard, his life would be forfeit. Curiously, he felt no fear, now that the last barrier between him and Leodegarius was removed.

He felt the Grey Knight's colossal presence within his skull, the warrior's essence blending with Uriel's and learning in a moment what had forged him into a warrior of the Ultramarines. Everything from the blue-lit caverns of Calth of his earliest childhood memories to the fight with the Lord of the Unfleshed became part of the Grey Knight's understanding and in the space of a breath, it was as though they had become one soul.

As Leodegarius learned of Uriel, so too did Uriel learn of Leodegarius, or at least as much as the Grey Knight wanted him to know. He saw the decades of battle, the years of study and solitude, and the complete and utter devotion to his sacred duty.

Leodegarius was a hero in the truest sense of the word, a warrior who fought for no reward, no acclaim and no reason other than that he knew he was one of a select brotherhood that was all that stood between humanity and destruction. Uriel saw unnumbered and unknown battles where the fate of worlds hung in the balance.

He saw triumphs and he saw losses. He saw victories and unimaginable sacrifice.

This was what it took to be a defender of the Imperium and Uriel's own achievements paled in comparison to what this great hero had accomplished.

Their lives intertwined in the space of a moment and the connection was so profound that Uriel began to panic as his sense of self was swallowed by the overwhelming presence of the Grey Knight's mind.

Then it was gone.

Like a sword pulled from a wound, the Grey Knight's power withdrew from Uriel's mind and he sagged against the chains that supported him. He dropped to his knees, suddenly feeling alone, so very alone, within his skull, as if a vital piece of him had been torn out.

In the face of the horrors Leodegarius had defeated, what did the life of a pair of Ultramarines matter? In the grand tapestry of the galaxy, Uriel's life was meaningless and he would welcome Leodegarius ending him now.

'Be at peace, Uriel Ventris,' said Leodegarius. 'A mind will always quail before its insignificance following union with a power greater than itself. Your warrior's pride will restore your sense of self-worth soon enough.'

Uriel looked up into Leodegarius's face, his handsome, perfect and magnificent face. The look of a great hero of mankind was etched into every shimmering line and curve of his skull.

'You saw inside me,' gasped Uriel, every word an effort. 'You know I am not corrupt.'

'You are not knowingly corrupt,' agreed Leodegarius. 'I sense no evil in you, but there are many forms of corruption. You may yet be a herald of wickedness and know it not.'