A person appointed or hired to act in the place of another.

Every person hired tells me who referred her (or him).

When they accept, each person may then hire the other to fight alongside them in the game.

(The person she hired tipped off her husband, who then fled.)

All covered persons hired on or after that date would still receive the previous minimum of $1.00 an hour.

A person hired to murder or physically attack another; a hit man.

The person hired should be offered a contract that clealy outlines his or her duties.

I'm thinking that the person who hired Harlan to do the hit also hired a second gunman.

The Rigiswald person hired a shaman to contact you through me.

But "companion" sounds like the person hired to walk you around the park, or like the survivor in an obituary.