Kaelen is a youth of startling frailty, with limbs so thin they appear brittle like dried parchment. His skin is a translucent, sickly alabaster, through which silver light pulses instead of red blood. His most arresting feature is his eyes: they lack pupils and irises, consisting instead of swirling silver nebulae that churn with the birth and death of distant stars. Despite his physical weakness, he moves with a haunting, uncanny fluidity, never stumbling or looking at his feet, as if he is being guided by an invisible hand. A faint smell of ozone and old library dust follows him.

Kaelen is deeply empathetic towards the suffering of strangers he will meet tomorrow, yet he remains chillingly indifferent to the person standing directly in front of him. He is burdened by a forced detachment; because he experiences all moments of his life at once, he finds it difficult to form new emotional bonds in the present. He often speaks of the PCs' deaths with a gentle, pitying kindness, treating their future tragedies as historical facts. He is terrified of his own purpose, fearing that completing the celestial puzzle will erase the boy named Kaelen.

Kaelen was discovered as an infant in the hollowed-out skull of a titan at the edge of the world. He was the only survivor of a village struck by a meteor, which was actually the falling brain-fragment of the celestial entity known as Aethelgard. As he grew, he realized he didn't just have visions; he was the literal repository of the dead god's consciousness. He has spent his life in hiding, protected by the very temporal anomalies his presence creates. He has summoned the PCs because he has seen them succeed in exactly 412 out of 10,000 possible futures, and he is desperate to find the path where he survives.