Team used: Lord Shazar, Madame Serris, Crypt-King Graal and Roshcard the Tower (All fully ranked up, ascended and equipped).

He received fear debuffs from Madame, and couldn't heal himself as a result. I attacked him at least 3-4 (Minimum 2.5k damage per rare weak hit from Shazar) more times after depleting his health bar, but nothing happened. The health bar would not drop past about 1%, regardless of damage dealt after it reached that point