Hearthstone‘s powerful Arena-exclusive cards are finally coming in the next patch—but they won’t actually be available for very long.

The cards will be added in the game’s 10.4 patch, which should arrive pretty soon. But they will then be removed from the Arena when the next expansion hits, and that should be sometime in April. Judging by previous expansion release windows, early April at that.

The timeline for the cards was revealed by senior game designer Mike Donais in a Reddit comment last night.

“Like most arena events they will be around for a while,” Donais said. “and then they will leave. In this case they will leave with the release of the next expansion. I think they are pretty interesting cards in general.”

Donais is right that previous Arena events, like Wildfest, have only lasted a few weeks. But it’s still a little disappointing that the cards fans helped choose back in November are only going to be around for a short time.

The card for each class was chosen by the audience of a panel at Blizzcon last November. From three choices presented, fans voted by acclaim for which they wanted to see introduced into the Arena. From the 10-mana Overload of Crackling Doom to the craziness of Polymorph: ???, these cards will be pretty fun if they turn up in your Arena draft.

Once these cards launch, make sure you spend some time in the Arena to enjoy them before they are gone.