In St. Pelin's deck, Reinforcements (3G -> 2G, C2:2P, C3:1P) is functionally superior to its upgrade card Legion's Arrival (3G -> 2G, C3:3P). At combo 3 they both do the same thing, but Reinforcements is more flexible at combo 2.
I was excited when I found out about this upgrade today...until I compared the upgraded card to the original Unless I'm overlooking some advanced strategy in which this might be actually considered an upgrade, I really do hope that this was an oversight and not the intended design.
This isn't exactly regarding the quality of the upgrade but does anyone know how to actually unlock this card? It's the last one I need and somehow haven't done whatever is required for the "upgrade".