Bayushi Paneki (Experienced 2) was first released as a rare in Web of Lies, generally considered by many players to be one of the more, if not most powerful, expansion sets of the current enviroment. Designed to be a true Master of Secrets, it was fitting that he revealed your opponent's hand and, once per turn per attack, allowed you to play a card from your opponent's hand. While his presence on the board did not generally win one games, it made it possible for one to strike surgically at the exact moment, giving the Scorpion a massive tactical advantage- something that was also reflected in his own Tactician trait. The latter also allowed Paneki to attack and in most situations single-handedly take down a province.
In Lotus Edition, Bayushi Paneki (Experienced 3) was printed as a fixed card in the Scorpion starter box as the Scorpion Clan Champion. This time around, Paneki had 3 potentially deadly abilities: he gained a permenant Plan Within Plans (Diamond Edition rare, allowed the player to take a Limited action during another player's Action Phase) as a trait, had the advantage of being able to constantly see your opponent's hand, and an ability which allowed you to swap one of your opponent's cards for one of your own, potentially trading something worthless to your opponent for something that he cannot do without.
Both Paneki versions are still being played these days, although the first would tend to see play more often in military-oriented decks, while the second would be more oft used in control decktypes.