Casual Undyne is a great monster that can quickly do lots of DMG to the opponent if not dealt with properly. When she kills a monster, the remaining DMG she dealt to that monster with will be dealt to the enemy player. This means that normally, if she kills a monster with 1 HP, the opponent will take 6 DMG.
This card works well against monsters with very low HP, so it may work well against bravery decks.
Since she is going to need to finish off the monster to make her effect activate, the best decks to choose would be Justice or possibly Perseverance which like to keep enemy monsters at low HP.
- 1 Damage (by Darky)
- Cooking Teacher (by Moonlightring)