The cavern was dark. The sound of falling moisture echoed throughout the blackness, unable to disguise the sound of chanting. Walker chose his steps carefully, not wanting to alert his quarry just yet. Deeper into the blackness he glided, his eyes picking up on a faint glow. As he made his way around an outcropping of rock, the glow intensified and resolved itself into a number of candles, their flames flickering in an unatural wind. The shifting light illuminated two major features of the chamber. First was a massive, upright ring of metal, with some kind of control system nearby. But the more important event in the room was the intracately designed circle drawn into the surface of the cavern floor- and the figure next to it. Walking around the perimeter was Sethos, his hand dripping blood onto the border.
Before Walker could debate the risks of disrupting the ritual, the area contained by the circle boiled away, and the cavern was filled by a keening wail. Another light filled the cavern, before being blocked by something massive. Walker blinked, trying to adjust for the varying light levels. When his vision cleared, he saw something that outstripped even his worst fears. Contained in the circle was a being, and Sethos stood with his arms outstretched, obviously intent on controlling it.
Walker stepped out from behind his cover, not wanting to believe what was before him. "Abis, what have you done?"
The quiet question was enough to break Sethos' concentration. He turned his attention from the circle and shot Walker a hate-filled glare, tinged with anticipation. The glare turned to shock as the summoner realized his mistake, and he refocused his attention on the creature now before him. But the momentary glance had been enough; with another keening cry, the beast escaped the confines of the circle and leapt into the shadows of the cavern, vanishing. Walker was quickly in pursuit, extending his staff just before the blackness swallowed him. Sethos stood by the remains of the circle, shaking in rage, before scooping up a black scimitar from the floor and pursuing the two.
The race was on.

His staff held in a ready position before him, Walker stepped silently through the darkness. Straining his hearing as hard as he could, he thought he could hear the creature's flight. The sound quickly diminished, leaving only the natural sounds of the cave. Walker began to circle the cavern, trying to re-aquire his quarry. As his path took him near where the whole pursuit had started, the circle, a faint rustling could be heard. Walker froze, tensed his muscles, and lunged at the sound, only to find empty air and solid rock.
Tense little thing, aren't you?
The whisper in the darkness made Walker whirl about, spinning his staff to block an expected attack. No enemy was to be seen, only the weak flickering of the nearly-extinguished candles. Walker began to move, trying to throw off his enemy's advance. He spoke in a whisper, "So. You're not just some run-of-the-mill creature, are you?"
Of course not. Although he thinks I am. His scheme is admirable, although he doesn't truly know what he has done.
"And I suppose he briefed you in that split-second before I distracted him. Right."
As I said, he doesn't know what he has done. That circle was meant for a lesser creature, to be sure. But he didn't read the ritual correctly. It was meant to be done by humans, with human blood. Your kind's blood, on the other hand-
"Allowed you to escape. Well, you're going back, one way or another, so it doesn't really matter."
Oh, I will be going back. But not the way you mean. When you distracted him, I took the oppourtunity to look into his mind. To know what he knows, and what he plans. That array, near the circle where I was summoned? It's a displacement device.
"A displ-?" Walker froze momentarily, now realizing the depth of his troubles. "He's going to-?"
Send me back into his past. When you and your friends of old were at their weakest, I will appear and slaughter you all.
"Thus, stopping us from getting in his way and halting his grabs for power. In a twisted sort of way, I'm kinda impressed."
Don't be. He won't be around to take power. He got one thing right with that ritual. Only his blood can render me powerless. His blood, and his family's. Of course, I can't allow that to happen.
Walker allowed himself to stop again, feeling the rage build within him. He was so intent on tracking the creature down that the appearance of a black-cloaked form went unnoticed. Walker started moving again, creeping along the edge where the candle's light faded.
The whispering continued. Still, this will be a first time for me. I've never been able to kill the same person twice.
"No offence, but you won't even be killing me once. You're finished."
Think again. A sharp, crackling sound filled the air, and the metal ring began to crackle with energy. As Walker turned to face it, the inside shimmered, then was filled with designs too intricate and numerous to see. He turned to face the darkness, to parry the attack from behind, but it was too late. A blur of motion, a flash of agony across his midsection- and Walker's body bounced, coming to a stop mere meters away from the ring.
The creature smiled, anticipating the bloodbath to come, and began to walk towards the upright ring. The rasp of metal against stone stopped it. It turned towards the sound, and there stood Sethos, fury radiating from him. Ah, so you did hear that.
"Yeah, I did." He brought his scimitar to a ready position. "Your flight's been canceled."
The young man charged, and the creature met his advance. Sethos swung his blade, trying to gut the beast, only to leave himself open to the thing's kick. Windless, Sethos was still long enough for the fiend to deliver an even stronger version of the same move, sending Sethos flying as well. A low, dry chuckles filled the cavern, and the demon strode towards the displacement device. Destiny awaits. As the creature stepped into the portal, the images within began to ripple. His vision clearing, Sethos drew on the last of his strength, and threw his scimitar into the control panel. The beast stiffened, and a muffled scream could be heard until it vanished through the barrier completely.
Sethos shakily climbed to his feet, and saw Walker's form lying brokenly on the floor. Moved by some unknown instinct, Sethos staggered over and raised his foe's head. Walker's breathing was ragged, and blood covered his face. His eyes opened, and inexplicably, Walker began to smile. "You... didn't realize what you were doing. I forgive you. I forgive you..."
Sethos was more stunned than when he was attacked by the creature. He'd expected a defiant taunt, or even resignation. But forgiveness.. "Father, I'm sorry."
"You didn't know. You didn't know." Walker's voice trailed off to a hoarse whisper, and his eyes closed. Sethos sat there, his father's head in his lap, until the sound of something falling drew his attention. He turned his head, and saw the black-cloaked figure standing there, silently watching. The same figure who had meddled in his plans even more than Walker; the figure who was somehow always there at the worst possible time. The clattering had been caused by the form's trademark mask impacting with the cavern floor. Sethos saw the mask, then looked into the face of his nemisis.
Into his face.
Sethos the Elder pulled his enveloping cloak over his head and tossed it to the floor by his younger self. Kneeling by Walker's body, he pulled a small kit from the pocket of his jumpsuit. Skillfully, he worked a small pill into his father's mouth, then looked at his younger counterpart. "You'll land about ten years before that thing appears. You'll find what you need to stop it in your journeys. And a quick word of advice- don't drink from the green cup. You'll understand what I mean." The younger Sethos let the elder take charge of Walker, picked up the black cloak, and slipped into it. Picking up the featureless mask he would spend the next few decades in, he strode towards the time portal.
Sethos the Elder had one last parting piece of advice. "Always remember who you are. Always."
Stopping in front of the portal, the younger one turned. "I am Abis Walker, son of Walker. In his name, I choose my path." Fitting the mask over his face, the young man turned back to the portal- and stepped in.

Though light may yield shadow, shadow need not always remain in the darkness.-- ancient proverb