Demon was a non-factor with Despara, Nanaly and Minerva smashing him with skills up

On a more general-use note, you want units like Bashira (NOT AW preferably; if AW you'll need AOE to clear out the others in her range due to her AW priority ability screwing with her in this map), witches (slowing him is good, very good), and pirates to burn him down. Uzume/Shuka skill is awesome here since their skills buff ALL deployed units' attack, so all your ranged people get the buff. If you're using Bashira/Nanaly/Elizabeth or units like Minerva/Beatrice/etc. (attack speed up skills), a dancer is good too.