Any relevant information that is not written on the card should at least be found in the legend
If you cast a creature with devour 1 and this ability gives devour 5, you get to choose one of them (probably the 5 since theres almost no downside to it)
That means the overall card has a red and white colour identity, so can only be used with Commanders that have red and white in their colour identity (Boros, Mardu, Naya, or Jeskai)
The highlighted cards here are "Mulan, Considerate Diplomat" and "Ariel, Singing Mermaid." The Amber/Sapphire deck includes various glimmers of an assortment of Disney princesses, and it's cool to see these classic characters with some new designs
At minimum, you can use this mana to give +3/+0 to a creature twice
within the original game, four potential dates are available depending on player choices leading up to this sequence