Molt Brother is an 1982 Science Fiction novel by Jacqueline Lichtenberg.
Humans are only part of the races within the wider Hundred Planets, an extensive galactic civilization. Another significant race are the Kren, snake-like humanoids with a unique physiology. Among other snake-like features, they shed their skins. The process leaves them vulnerable and helpless for a while. Someone needs to help them through the traumatic event. So the Kren choose a "bhirhir" (molt brother), a non-sexual life partner. Arshel Holtethor Lakely, a young female Kren with the power of Psychometry, has chosen poorly. Her human partner turns out to be a ruthless individual, whose limitless ambition make him capable for any act of betrayal.
The ambition of said partner, Dennis Lakely, is to locate the Mazeheart Object, an artifact sought by archaeologists and political factions the galaxy. It is the last remnant of a previous civilization, and is rumored to be the key to absolute power over the current one. The endless quest has its price. Something which Zref Ortenau MorZdersh'n, a young human boy, has just begun to understand. His parents were experts on ancient languages. He and his molt sister Sudeen were going to follow the same path. But an attack organized by an unknown party resulted in the deaths of his parents, and Sudeen. He is now alone.
The paths of the Arshel and Zref are eventually going to cross, the search for the Mazeheart being only part of the plots and mysteries lying ahead of them. The novel has a sequel, City of a Million Legends (1985).