What is Infuse in Hearthstone?

Hearthstone has many card effects that are common enough that they get their own keyword - a word or two that immediately tells you how the card works. Let's take a look at the Infuse keyword.

Upgrades in hand after X friendly minions die.

Infuse a keyword added into the game in Murder at Castle Nathria. Cards with Infuse have a number associated with their Infuse effects, and after that many friendly minions die while you hold the Infuse card in your hand, the card will upgrade with new art and will say "Infused" on them. This is very much like Corrupt from Madness at the Darkmoon Faire.

Keywords that Work Great with Infuse

Minions with Charge or Rush can be used to upgrade your Infuse cards as they can attack right away and potentially die on the same turn. Taunt minions can also be quite useful as it prevents your opponent from merely ignoring your minions and therefore halting progress on your Infuse cards upgrading.

Since the mechanic also relies on friendly minions dying, Deathrattle minions have a natural role in upgrading your Infuse cards as they'll be providing you with additional value in your gameplan. Some Deathrattle minions may even summon other minions and therefore upgrade your Infuse cards quicker. Reborn from Saviors of Uldum can similarly be used to upgrade your Infuse cards quicker by acting as two deaths.

Classes that generate Lackeys can also benefit from this as they're 1/1 minions and as such, can die pretty easily, and many decks that also make several of them. Colossal minions also spawn other minions naturally. Minions with Echo can also be played multiple times in a turn, putting more minions on the board. Basically, anything that summons multiple minions at once will naturally be useful with Infuse.

Playing Against Infuse in Hearthstone

Playing against Infuse is difficult to do directly as it's not necessarily obvious if your opponent is holding an Infuse card, and killing your opponent's minions is also something that will just naturally happen over the course of the game.

If your opponent is playing many cards that summon several minions at a time, then you may have reason to suspect your opponent is playing Infuse cards, or is even currently holding at least one. Note that Infuse progress can happen on either player's turn meaning that even if you ignore your opponent's minions and attack their hero, they may still be able to trade their minions in and upgrade their Infuse cards.

If necessary, minions can be removed without killing them via returning them to your opponent's hand or deck. Freeze effects can also be used to prevent their minions from trading into your own minions.

In the event that your opponent controls multiple fairly strong minions, it may be better to just simply clear the board as normal. Even if this does upgrade their Infuse cards, the chances are that dealing with an upgrade Infused card will be easier than a full enemy board. Infuse cards will naturally also require them to be held in your hand and wait for minions to die to be upgraded, so you may notice your opponent holding a card in hand for multiple turns waiting for it to be upgraded.

Example Hearthstone Infuse Cards

Door of Shadows is a 1-mana Rogue spell that simply draws another spell when played. It has an Infuse effect that adds a temporary copy of the spell to your hand (in a very similar vein to Echo cards, however you can't play multiple of them in the same turn) if 2 friendly minions die while you hold the card in your hand.

Priest of the Deceased is an incredibly simply implementation of the Infuse mechanic, as it simply just gains +2/+2 if 3 friendly minions die while it's in your hand, becoming a 2 mana 4/5 with Taunt.