Terrakion's Retaliate one-shots Darkrai, so I don't know why you think only EXs work against EXs. Zekrom's Bolt Strike also does a lot of damage and doesn't lose in the prize trade; it one-shots Tornadus EX and Kyogre (lol Kyogre), and what it does not KO it severely maims.LOL! I don't wanna come across as a horrible Pokemon, and I want to tell you this... Zekrom/Reshiram aren't that great, I'd suggest using EX's, because only EX's work against EX's.