Name: Sid Ketchum
Inspired by: Possibly Tom Ketchum, cowboy, cattle driver, train robber, and murderer hung in 1901 for attempting to rob a train. However, "Black Jack" was Tom Ketchum's nickname, and so seems to be Black Jack's nickname. It seems strange that Tom Ketchum inspired two characters. I am sure there were more Ketchums and Black Jacks that could have been the inspiration for these two.
Life Points: 4
Ability Type: Defensive
Ability: At any time, he may discard 2 cards from his hand to regain one life point. If he is willing and able, he can use this ability more than once at a time. The BANG! FAQ spells out that Sid Ketchum can use his ability out of turn: "Q26. Can Sid Ketchum use his ability even outside his turn, like a Beer card? A. Yes, he can."
Activation: Whenever Sid Ketchum has 2 cards in his hand and chooses to play them. These cards can be discarded even like a last second beer (See Emiliano Sciarra's discussion for this).
Cards enhanced by Sid Ketchum's ability: All cards except Beer, but especially Wells Fargo and Stagecoach
Card weakened by Sid Ketchum's ability: Beer (except in 2-player), Volcanic
Cards more effective when played against Sid Ketchum: Panic, Cat Balou (when targetting his hand), Jail
Cards less effective when played against Sid Ketchum: Duel, General Store
Characters who counter Sid Ketchum well: Jesse Jones
Ideal Roles for Sid Ketchum: Sheriff, Renegade
2-player Value: Okay. While it may seem very beneficial to still be able to gain life points when your opponent cannot from Beer cards, Sid Ketchum has to discard 2 cards to do so. Since Sid Ketchum will be the other player's only target, this may not be as useful as it seems. It can be good to get rid of cards in excess or cards that cannot otherwise be played (extra BANG! or Beer that can be played but has otherwise no effect), but it is far more limiting than before. It is only particularly useful if Sid Ketchum can create distance between himself and the other player. Sid Ketchum might try to use the cards as last second beers, and if he is not shot, use the ability when he gets more cards.
General Strategy as Sid Ketchum: As with many characters, the most important thing to do first as Sid Ketchum is to remember that he can use his ability whenever he has 2 cards in his hand. The ability to voluntarily discard cards is also very useful. Remember that each player can only have 1 card in play in front of him that has a given name. If he has another card with that name in his hand, then he cannot play it, so it is stuck in his hand unless he Cat Balous it from his own hand or he discards it when he is over his card limit. It is much better as Sid Ketchum to be able to discard this card to gain life points instead of just burning it. This is also true of Beer if Sid Ketchum survives until there is only 1 player left. Other players have to discard the card or use it with no effect, while Sid Ketchum can at least discard it to contribute to the cards needed to activate his ability. I enjoy having Sid Ketchum discard Saloon to gain health as well.
While Sid Ketchum has more "lasting power" due to his great defensive ability, I wouldn't draw too much attention to him. It is better to try to attack players who are in Sid Ketchum's range, but he is not in theirs. This way Sid Ketchum will only have to focus on using his ability when hit by "no-distance" cards such as Duel, Indians!, and Gatling. When it comes to Duel, it is often better for Sid Ketchum to just take the hit, unless he has a great chance of hitting the other opponent and he is not opening himself up for attacks from other players. Each BANG! card Sid Ketchum expends is essentially 1/2 a life point, and not having them in his hand for possible Indians! should really make him think twice before you play any of them. When a player next to Sid Ketchum attacks his, instead of responding back with aggresion if that player is in range, it can be a good idea to attack another player (which preferably cannot hit Sid Ketchum back). This will often surprise the initial player who attacked Sid Ketchum, and have make him wonder if he is on Sid Ketchum's team. I would only recommend doing this if there is another person that that player can target. Many times in BANG! we shoot at another player simply because we have excess BANG! cards and have only 1 player we can reach. Your confusion will probably not overcome this hurdle.
I wouldn't get too anxious to convert all of Sid Ketchum's cards to life points as soon as he can. Even cards that do not look (even are not) useful can be good to keep in Sid Ketchum's hand. Since other players do not know what those cards are, they create a sort of "imposing front" that may keep other characters from acting against Sid Ketchum. If Sid Ketchum removes all or most of the cards from his hand, then other players will have no problem attacking him. Keeping the cards in Sid Ketchum's hand is less problematic since he can play the cards at any time, even as less second beers. Of course, by keeping the cards in his hand Sid Ketchum is still taking a risk: perhaps a player will Cat Balou or Panic a card from his hand so that Sid Ketchum can no longer convert it. Such is BANG!
General Strategy against Sid Ketchum: When playing against Sid Ketchum, the main thing to do is to remember that his cards are his life points. Anything you can do to get him to expend his cards is in some sense taking away Sid Ketchum's life points. If he plays BANG! because of a Duel or an Indians! he has expended 1/2 a life point for each card. Thus, Cat Balous and Panics from his hand are very impactful, especially if the stolen card is an offensive card that you can use right back at him. Jails are very effective against Sid Ketchum as they keep him from replenishing cards during his drawing phase. Along these lines, you should be very careful when playing a General Store. If Sid Ketchum's health is low or you are trying to weaken him severely, you need to carefully weigh the pros and cons of giving Sid Ketchum another card. Oh, and as a good strategic rule (albeit not a kind one), I wouldn't remind Sid Ketchum when and how he can use his ability.
Besides this, Sid Ketchum is not the worst character to face one on one. The biggest difficulty is if you are stuck with Sid Ketchum and one of his team mates alone. Attacking Sid Ketchum is difficult because he can always burn the 2 cards he draws each turn to gain the life point you took away back, while his team mate shoots away at you. If you are stuck in this situation, for which I feel sorry for you, try to eliminate the more offensive character first and then try to deal with Sid Ketchum.