The Lantern of Osiris is an artifact created by the WarlockOsiris to aid in his experiments with time on Mercury. He later gifted the Lantern to the Young Wolf to help in their exploration of the Corridors of Time to undo the damage Osiris' experiments caused.
"I created the Sundial to rectify my greatest regret. I failed. And now the Red Legion has turned my failure to catastrophe. Time is broken on Mercury. It has taken all my resources, all my Echoes, to monitor the timestreams the Legion has created on Mercury. So this Lantern is yours now. To light your way from time to time. May it serve you better than it served me." —Osiris