After the first set of cards in Legends and a few other sprinklings, many of which established that gold cards would be consistently more powerful than their competition, gold came into its own in Invasion block
Here's the low-down on Disney Lorcana card sizes: Why does Disney Lorcana card size matter
You must sacrifice exactly one creature to cast this spell
For example, if there are two +1/+1 counters on Aerith Gainsborough and it gets three -1/-1 counters, you'll put two +1/+1 counters on each legendary creature you control when Aerith Gainsborough's third ability resolves
Hes not the most capable card with his base stats, having just 1 Strength and 2 Willpower, but he does get an extra 2 Strength when hes Challenging, thanks to the Challenger +2 keyword
The cost reduction applies only to generic mana in the total cost of spells you cast with the permission granted by Urianger Augurelt's last ability