If the opponent Kaalia attacked is no longer in the game when its ability resolves, you may put an Angel, Demon, or Dragon creature card onto the battlefield tapped, but it won't be attacking anyone and it won't be an attacking creature
What can the cards be about then, in this context
Your constructed ranking is based on how you perform in games where you get to use cards from your collection to craft a deck
Notably, casting a multicolor card will trigger two or more of these abilities, making Aragorn more efficient and rewarding for players using him in a color-heavy deck with lots of multicolor cards -- of which Tales of Middle-Earth has plenty
Because of that, expect to see him see play in decks in which life-gain and exploding spells are both included, such as a R/W deck that runs Congregate and X-damage spells or to fuel a giant Exsanguinate in B/R that uses Kokusho-style cards