Walter Picardo Tenson is a fictional Trill-Betazoid 24th century Starfleet Officer.

Being the first half Trill to be joined with a symbiont, life is not easy for Walter. After joining with the Nost symbiont the two separate minds merge to forming a new personality who is a combination of both Walter and the Symbiont. This causes severe psychological problems to Walter since he's joining was force upon. He had no intention or hope of joining with a symbiont for he is not a full Trill and have received no training whatsoever of coping with the symbiont. Furthermore, he had always have a tint of guilt about agreeing to the operation as Nost might still be alive if he didn't.

As the Beta species of Trill, Walter has a narrow speckled band running along the hairline to the sides of the neck, then down along the body. Beta's host and symbiont also become physically and telepathically dependant on eachother within 93 hours of the joining; after this period, removing the Symbiont is fatal to the Host. Joined Trills are also allergic to insect bites, since the biochemical connections of the symbiont and host can't tolerate the toxins; however, they are more resistant to a noxious paralyzing volcanic gas than other humanoids such as Bajorans and have more overtly developed senses include identifying a known individual only by the audible rhythm of footsteps.

The Betazoid part of Walter enable him to have Inter-species telepathy and emotional empathy with most other species whether on board the ship, in a ship at close proximity or on the planet below. However, it is also this because of this Walter have a harder time to cope with his symbiont. It enable him to actully talk to the symbiont as another person and not a part of him.

Rear Admiral Tenson is currently the second Executive Officer for Task Force 38, and CO if the Akira-class USS Tornado (NCC-74080).