The Chronoplast

The Chronoplast was the largest of the Time Streaming devices in Nosgoth, and it once belonged to Moebius. It is unclear whether or not he was its architect, but it was capable of creating portals that would allow him (or anyone else) to travel through time.

The Chronoplast device was built into a large room with multiple tiers. On each tier there were several clockwork mechanisms. By manipulating these mechanisms, Moebius could select the period of Nosgoth's history he wished to visit. A claw-shaped piece of machinery was mounted on the high ceiling, and it spun with increasing speed as the Chronoplast was activated.

The Chronoplast was concealed deep within a mountain to the north of Nosgoth. Kain visited the mountain in Blood Omen to see the Oracle of Nosgoth. He never realized that the Oracle was actually Moebius. The meeting took place in the cauldron room of the Oracle's Cave, and satisfied with Moebius' advice, Kain did not progress beyond it. He was apparently unaware of the Chronoplast's existence for quite a while.

By the time of Soul Reaver, Kain was very familiar with the Chronoplast device. Sometime after Moebius' death at his hands, Kain probably returned to explore the cauldron room further, and found the hidden passage that led down to the Chronoplast. It is likely that his whole plan for shaping Nosgoth's destiny - including the execution of Raziel - was formed after observing Nosgoth's past and possible future through the Chronoplast, and the star portals in the corridor outside. As he said to Raziel in Soul Reaver, the Chronoplast offered "insight for those patient enough to look".

Raziel followed in Kain's footsteps in Soul Reaver. He discovered the secret passage from the cauldron room, and he negotiated the various obstacles between himself and the Chronoplast. He intended to confront and destroy Kain who was there, awaiting his arrival. When they met, Kain told Raziel how he had discovered the Chronoplast centuries before, and described the nature of destiny and fate: free will was an illusion.

Raziel and Kain fought, and - in-between blows - Kain set the Chronoplast mechanisms, opening a new portal into the past. There is some discrepancy between Soul Reaver and Soul Reaver 2 at this point. In the former, Kain was visibly exhausted by the battle, which was more drawn out as the last 'boss' fight of the game. In the Soul Reaver 2 FMV of the same events, he was supremely confident and easily rebuffed Raziel's attacks. At the end of the skirmish, (in both games) Kain entered the Chronoplast portal, compelling Raziel to follow.

Raziel ended up in the Sarafan Stronghold, thirty years before the events of Blood Omen, and was met by Moebius. Kain was nowhere to be seen, and Raziel had to go to the Pillars to find him.

FURTHER OBSERVATIONS

It appeared the Chronoplast could allow its users to travel through both time and space. This did not seem to be the case with the smaller Time Streaming devices in Soul Reaver 2 - when Raziel used them he always remained in the same device, he just found himself in a different era. It's a bit inconclusive however, as Raziel did not have an in-depth knowledge of how the devices worked. He couldn't adjust their target without Moebius' help, so we can't be sure what they were capable of.