A sterika was a close bond between two members of the Adnerem species of the planet Adner. The bond was always between members of the same steris, the name for an Adnerem family, and entirely non-sexual, but the Adnerem would become so close they thought of themselves as a single entity. At any one time, about ten percent of the Adnerem population was in a sterika, and while Adnerem did not actively seek a partner to form a sterika with—as other species sought love—those Adnerem not in a sterika often appeared envious of the close bond between those who were. It was incredibly rare for Adnerem to form any other kind of strong emotional attachment to a living being.