Senuhet is described as a small, old, slender man. He is bald, with olive skin, most probably of Egyptian or Yemeni heritage. Senuhet's upper eyelids are painted with Kohl (a type of middle-eastern cosmetic used to blacken the area around the eyes), with two black lines running from the corners of his eyes to his ears; his chin is also painted with three white lines. He has a heavy accent when speaking English, and uses ancient Egyptian when speaking to his master. This, combined with the fact Dr. John Dee regards Senuhet to be his senior, may suggest that Senuhet was born in ancient Egypt.
In The Alchemyst, the The Crow Goddess instructs Dee to recruit Bastet to help in the siege of Hekate's Shadowrealm. Dee travels to Bastet's Bel Air estate, where he is greeted by Senuhet; Senuhet claims that he has been at that particular location for "Less than a hundred years. No time at all, really."
The following day, Senuhet participates in the siege, wielding two bronze Khopesh (curved swords used in ancient Egypt). He plays a minimal role in the fight, though he survives unscathed (albeit one of his swords is lost, and the other snapped in half). After the battle, Dee uses Necromancy to interrogate Hekate, though his interview is cut short as the Shadowrealm collapses - Senuhet, who is limping, is too slow to escape. Despite his pleas for help, Bastet leaves him behind, and he is turned to dust.
Immortality: Senuhet gained Immortality from his Dark Elder masters, and therefore does not age (though he is vulnerable to injury and poison). Unless his masters choose to take his immortality away, Senuhet may live for thousands or millions of years.