Walpurgisnacht is the most dangerous enemy from the entire Madoka Magica collab. This is because her Omni Strikes can hit up to 1500 range away from her and slow units somehow surviving it, complete with Base Destroyer and her fast attack rate. Also keep in mind that like all Witch enemies, she is not considered a Floating enemy despite aesthetically being in the air.
Strategy[]
Surprisingly, this enemy becomes very easy to beat if you have unlocked both Li'l Madoka and Li'l Homura and use them in battle. The Cat Combo called My Very Best Friend involving these Cats will further improve the effect of their Witch Killer ability by a massive factor. You can use also any of the Uber Rares from the collaboration should you have received them; see here for a list of units who have the ability. Of them, Homura has the best matchup due to her slow immunity, allowing her to recover immediately if she is ever knocked back. Without Witch Killers, the battle becomes more challenging if not outright impossible.
Alternatively, you can use Stone Cat boosted with combos to slowly drain its health, but be aware that in higher magnifications, Stone Cat can and eventually will be destroyed immediately due to the massive Critical damage, and using it alone takes a long time to win. Still, Stone Cat can work wonders with stalling Walpurgisnacht while other units deal damage. Even if you don't have Stone Cat, you can use talentedJiangshi Cat and speed combos. Keep in mind this only works with a M speed combo and maybe lvl 8-10 or lvl 10 with a Sm speed combo. You also need Slow Resist to a good level so that it can move forward as soon as the knockback animation finishes.
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Walpurgisnacht is also the name of a German holiday. Walpurgis is a celebration commemorating Saint Walpurga starting on April 30th and ending on the 1st of May, while 'Nacht' means 'night' in German. Walpurgis is commonly associated with religion and celebrations and, like many things associated with religions, also with witchcraft.
She is the first and currently the only enemy to have a Critical chance of 100%.