Fusion is a keyword mechanic introduced with the Set 9: Doombringer set.
During deckbuilding, players can take two troops with Fusion and combine them into one troop… permanently!
The new troop will have all the combined cost, thresholds, attack, defense, and powers of the two combined troops. Crazy awesome, right? Words don’t quite do it justice, so I think it may be easier to show you than try to explain exactly how this works:
Once you’ve fused the troop, you can put your new creation directly into your deck, whether it’s for Standard, Frost Ring Arena, or Limited events. Of course, when it comes to limited you will have to have drafted or opened both halves of your Fusion cards to build your new troop.
The Fusion results are called Ender Terminus.