The card just says the "first person to point it out," so they have until the game ends
Legends represent characters with roots in the past
That said, neither of those strategies are popular at the moment
Some of the sorceries from the Face the Hydra deck might also work, as long as your group is willing to interpret the word Heads as creatures and think of the Chaos Deck as being the Hydra. For example, Unified Lunge would read, Unified Lunge deals X damage to each player, where X is the number of creatures on the battlefield. And Disorienting Glower could be interpreted as, Players cant cast spells until the next time a Chaos Deck card is played . Similarly, you could include some of the sorceries from the Battle the Horde deck by swapping out the word Minotaur for creature. Consuming Rage would then read, Whenever a creature attacks this turn, it gets +2/+0 until end of turn
Even if the matches against it are often exciting, no new cards from the Deluxe Pack EX unfortunately ensured we got another month of their 'rain' of terror
There's also a chance to uncover highly coveted Borderless Planeswalkers and Ancient Dragon cards