Yenkya

Yenkya, the Red Sage, is one of the oldest known Pre-Cycle Protobeings alongside Suyarii. For most of her existence she dwelled within the Library of Yenkya, as her existence was not part of the cycle, and much of the knowledge she held was forbidden by Goldenlake, causing her to be erased if she were to ever leave her library. With the end of Cycle λβʹ - Defiance, however, she was written into Goldenlake and is now free as of Cycle λγʹ - Renewal.

Cycle λαʹ - Betrayal

Near the end of this cycle, Yenkya contacted Eurar and made a deal with him, during which he gained schematics to reach Goldenlake.

Later she also made a deal with Kiran Ciel, which resulted in her storing all of his memories. She would later restore them to Kiran's iteration within Cycle λβʹ - Defiance, Jaelin.

Cycle λβʹ - Defiance

At some point during this cycle, Yenkya made a deal with Suyarii, and removed their memories, allowing their consciousness to be reborn as the dream companion of Cassidae under the name Sylfia. The details surrounding this deal are unknown.

Later in this cycle, Yenkya saved the Keepers of the Radiant Flame from Eurar's attacks and explained the concept of cycles to them, as well as offering to teach them the Final Song so they could reach Goldenlake and reconstruct their world into the next cycle. In return, the key to translate Goldenlake, later revealed to be Suyarii under the identity of Sylfia, would write in Yenkya's existence so she could safely leave her realm.

At the end of this deal, she returned from Goldenlake after the Keepers had already departed and restored Suyarii's memories.

Cycle αʹ- Origin

During this cycle, Yenkya gained the ability to survive the passing of cycles by

Surely you've heard that knowledge is power, no?

And so, by extension, knowledge of a being is power over that being, don't you think?

This piece of knowledge is one I believe is best left unknown.