Dusty woke up slowly, the ice on his coat making his body numb. Hard floor practically made of ice and sediment, the colt coughed some of the dust out of his throat and tried to get a fix on just where he was...the only marking he could see in the thick dark was a boulder smashed into the ground and a beam of light pouring over it from the hole it left in the ceiling. Dusty managed to stand up after some struggling with his heavy limbs, shaking the ice off his thick metallic coat while his eyes adjusted a little better; the sound of ragged coughing brought back a piece of a memory...Sentinel sailing through the air with blood spilling on the velvet rug...
"Sentinel!"
Dusty ran to the sounds of the injured guard, stopping dead in his tracks when the thick frame of the king of shadows came into view. Once Dusty's eyes fully adjusted to the dark he saw Sentinel laying on the ground, a blood splatter nearly four feet above where he lay against the wall.
"Get away from him!" Dusty shouted in vain...
Sombra shot his son a glare that put ice in the colts veins; making his already heavy limbs just that much harder to move.
"What did you do?!"
Sombra glared back down at the guardpony...contempt rising but a pain in his chest from the long trip with two ponies in tow and his own personal bout of gloating took its toll on the king. Now though his focus was on one last task, the last of his power regained would be put to good use...
"Dad...what did you do?!"
The pain in his chest grew...dark magic began to form at the deep gash in the guards neck, lightning singeing the guard white coat but soon the flesh began to rapidly repair itself. The world began to swim and it became almost impossible to keep going...but he still did. After grueling moments pushing what little power he had left into the guard...the wound closed and became a black scar covered by white fur.
All the broken king felt was the cold ground when his head slammed into the shards of rock, body emitting the last of his physical form in black mist and eyes devoid of emotion. This was it...there was no more aces he had left; no way of escaping death and with no plan to run though his head, he got to think of the more dire realizations...
I....I have a son.
Dusty ran past the king and did what he could to help Sentinel, ignoring the fact that his only father was fading into nothingness. Strangely though, he was not angry for Dusty leaving him...
He did nothing to deserve being..used like the rest of them.
Nothing mattered to him..it was only about revenge for a crime long forgotten in time, he wondered if Celestia even had the decency to remember her crime; though at this point it didn't matter. The only thing he knew in life was vengeance; born out of hate. It was only when he almost pulled off his greatest plan...ruining a new alicorn; destroying the hopes of an old one, and even starting a new legacy of darkness.
So why do I feel so empty...?
The king of Shadows saw ash rise off his hooves as the pain in his chest became unbearable; thoughts of the afterlife crossed his mind over and over. One thing kept dragging him back to feel that pain, there was no mercy of letting the darkness in his eyes take the pain from him; the guard even managed to get up and drag his son away from his fathers burning echo, entertaining the idea that Dusk might have some feeling left reserved for his soulless father. No mater what though, Dusty has seen what the power of dark magic truly does...even if he may be repressing the gruesome details, he now understood why Sombra was hated. Why his father was kept secret...and why Twilight was ashamed to fall under his spell.
"What...is wrong...with me?"
It looked like Dusty said something in return, but the pain made his ears ring out any semblance of comprehensible sound. Reassuring words lost to guilt or spiteful insults meaningless in the final moments...Sombra felt the pain on the verge of finally taking him when he finally understood...
I have a son...and threw away my only chance at...
"I...don't want to die."
With that...Sombra finally got to feel the fires and blaze of Tartarus after such a long and dim run. Leaving his traumatized son and a near dead guard in the middle of a broken keep in a frozen tundra...