It is a close combat card with a strength of 7, and the ability to destroy the opponent's strongest melee unit(s) if their combined melee strength is 10 or more. Although this effect looks similar to Scorch, it only targets enemy melee units. Therefore, this card is very powerful when used right, since it has the ability to lower the enemy's combat strength while adding 7 points to your own.
It is extremely powerful when Biting Frost is active should the enemy have a melee hero placed (which is unaffected by weather cards) or more than 10 regular units (commonly happens when fighting against a Monster deck), since all melee units will then have a strength of 1 (or 2 with commander horn/Dandelion). This means when Villentretenmerth is played, it will destroy every regular melee unit on the opponent's side.
The effect may be less effective against Northern Realms and Nilfgaard since some of their melee units have the Tight Bond ability. In that case only the cards affected by Tight Bond will be destroyed, as they'll have a stronger combat strength than regular ones.
As a melee unit, it is vulnerable to Scorch cards and your opponent's Villentretenmerth, should they have it. However, as a unit this also means you can call it back with a medic or a decoy, allowing for a second (or third) strike.
- See the GWENT standalone game version card: Villentretenmerth