Every so often a new mechanic gets released into the hands of Magic players far and wide that shakes up a format completely, and Legacy is no exception. With the release of Commander Legends: Battle for Baldur's Gate came a mechanic that introduced "the initiative", an expansion on the Adventure in the Forgotten Realms Dungeon mechanic. The initiative creates its own unique dungeon , the Undercity, for players to go through and gain value, and its power level far exceeds the previous dungeons. 
The Undercity offers a wide variety of different rooms with potent abilities, and Legacy players were quick to notice. Running through the left side of the Undercity each turn sets the tone for how a match is going to play out, starting with searching a basic, increasing the power of a creature , draining an opponent for 5 life, drawing a card and finally digging through the top of your deck for a finishing creature to clean up the match. Often times this will be enough to outright end a game. While not every card that takes The Initiative is incredible, there are a few that stand out above the rest. 
White strategies saw the most love with two incredibly powerful cards Seasoned Dungeoneer and White Plume Adventurer both of which curve right into each other perfectly. This paved the way for a new deck to emerge focused around slamming these down and dominating your opponent. The value these cards can generate is second to none with this mechanic demanding players have an answer right away in the form of counter magic, or a faster creature strategy to take away the Initiative. Red decks also saw a decent card in Caves of Chaos Adventurer with prison strategies plugging her in to finish games quickly and gain card advantage. While these might be the more powerful initiative cards, the lesser known cards are still playable.
Legacy rarely changes to a degree where its considered noticeable, however with these cards making their way into decks its certainly refreshing to see and absolutely noticeable. Over all I think additions like these are healthy for the format and pushes players to think outside of the cookie cutter mindset of "a deck is only good with xyz" The Initiative is definitely something to have on your radar as you assuredly will face off against it at some point. These are cards you don't want to sleep on.
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