This mural seen in the Flopside Pit of 100 Trials in Super Paper Mario presents a very interesting piece of lore continuity between two separate timelines in the game that is never explicitly stated. While the mural at first glance simply depicts King Croacus IV, the boss of Chapter 5, with his Pure Heart, it is apparent upon closer inspection that while he is red, the flower in the mural is black. This is because it actually King Croacus I, the great-grandfather of the boss fought in-game.
It is established in two separate places that:
-The Ancients created the Pure Hearts 1,500 years prior to the events of the game.
-The Floro Sapiens have their own calendar according to which the game takes place in the year 1626. King Croacus I ruled from Year 1 to Year 496.
Cross-referencing these two gives the result that 1,500 years before the game was the year 126, within the reign of King Croacus I, so he would have been the one in possession of the Pure Heart at the time assuming the murals were made at the point where the Pure Hearts were given out to their guardians.
All of this can only be gleaned by the players cross-referencing the dates on their own instead of ever being explained in-game.
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