Deep Space Nine's flat-featured Security Officer is one of the station's most trusted members of staff, despite his true, slippery form.

Every 16 hours Odo is forced to revert to a state of orange fluidity, and is capable of changing his human form into a spectacular variety of shapes. It is this ability that earned him his rather unflattering name. (Odo is an abbreviation of the Cardassian word 'odo'ital', which roughly translates as 'nothing' or 'unknown').

Respected for his broad-mindedness towards other life-forms and devout pacifism, Odo has successfully resisted using any type of weapon in his job as security chief. Yet his commitment to upholding justice is as unflinching as his attitude to violence. He has asserted more than once that 'laws change, but justice is justice'.

Odo quickly earned the admiration of Captain Sisko on Deep Space Nine and has had romantic feelings for Major Kira, but has received no encouragement thus far.

Knowing only that he originated from an alien world somewhere beyond the wormhole, Odo spent years trying to discover his true identity after being discovered as a baby in the Denorios Belt near Bajor, 50 years before the DS9 series began.

Working on Deep Space Nine before the Federation took control, Odo was forced to entertain the Cardassians with demeaning shape-shifting routines, instilling in him a sense of isolation. He has since discovered that he is one of the Founders of the Gamma Quadrant's Dominion, just one of 100 infants in the species sent into the far reaches of space. Odo's reunion with his fellow shape-shifters has bolstered his confidence and improved his social poise. He has recently stopped sleeping in a bucket.

Rene Auberjonois was a well-known face on US television before landing the role of Odo, and also played - uncredited - Colonel West in Star Trek VI: the Undiscovered Country.