The Pyromancer is a ranged spellcasting unit aligned with Red Mana, because of course, and their spells affect the battlefield as well as your foes.
The new Magic Legends story chapter is Act IV: Chasing Answers, where the Planeswalker makes itself known in Benalia.
Some of the QoL enhancements include a quick play feature that lets you choose a story and ordeal before adding you to a quick play queue immediately, plus some streamlining to the start of the game for new players.
All this is in addition to a slew of improvements to the overall experience, and you can check the full patch notes out on the Magic Legends blog.