Sadly, this is held back by only getting one trigger per turn, but not the worst overall
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The shear number of things this could set up makes it really hard to tell, so I kind of have to leave it in the void of speculation
5 Shadow of the Enemy Yes, Shadow of the Enemy requires a lot of mana to make work, but there are plenty of ways to get a lot of mana even in Tales of Middle-earth (Smaug would like to give you 14 treasure tokens, just as an example)
That being said, however, you can definitely expect this card to be expensive
That can be done with cards like Spark Double, or the passive ability of Nicol Bolas, Dragon-God