Seagrave Holmes was born in 2247. Now aged 30, he is a genius tinkerer and fixes anything he can get his hands on. He spends his days in the shop, and at night, he hangs around the Weatherly Hotel to talk to Vera Weatherly, who he's not-so-secretly in love with. Seagrave has that easy way of relating to common folk. He fits into their social world without even thinking about it. While he is exceptionally gifted with machines, he never lords that over others.
In his shady past, he used to do business with the slavers of Paradise Falls, but now he merely runs a general store in the marketplace called "Rivet City Supply". According to Doctor Preston's terminal, Holmes suffers from a chronic case of red-lung from all his repairs below-decks.
Seagrave is generally to be found in his shop or (often on the flight deck), trying and failing to woo Vera Weatherly. He can also be found leaving his room, (mid-deck next to marketplace entry) around 2-4 am. The Lone Wanderer can overhear that she does not want to be with him as he reeks of sewage.
The Wasteland Survival Guide: If you are working on the Wasteland Guide quest, he is one of the persons to talk to in finding out the History of Rivet City. If you go speak to Vera Weatherly about Rivet City's history she will direct you to talk to Seagrave, and if you then speak to Seagrave, his speech makes it obvious that he has a crush on Vera.
Council Seat: Bannon mentions that his council seat is being contested by Seagrave. He wants you to look for incriminating evidence against his opponent.
pcxbox360ps3 If you sided with Bannon during Council Seat, then his dialogue changes. His quote before his trade interface is "After what you did? Only because I have to." His lips do not move during 'After what you did', but they do for 'Only because I have to'. [verified]
xbox360pc Seagrave can disappear from the ship, not to found on the ship or at his shop. [verified]
Due to this bug both Seagrave and Vera Weatherly end up inside an unaccessible building near makeshift supermutant camp north of Project Purity, engaging in endless looped conversation. Teleporting them back to the ship using console commands on PC seems to fix their behaviour.