Again, the same as Ethics Gradient said. Developer's choice in publishing brand-new material. The original tabletop Rise of the Runelords had three stat-boosting spells: Glibness, Speed and Strength. These translate to Eloquence, Agility and Strength (why the name-changes? Agility understandable, I think, but Glibness?). The developers could maybe add the remaining stat-boosting card (Toughness and Sagacity are in the game as uncommon treasure cards). So when they added Mass <something>, they added the whole lot of them at once as they are at the same level, but probably forgot Brilliance.
The name change is because in the paper game they want every copy of the same named card to act the same, and presumably that includes the digital game.