[quote=@MelonHead]
Honestly, I'm not sure why Holy Magic specifically is so under-used in Arena, I seem to be one of the only people who has recognised half the people you fight are evil spirits or undead or demon-vampire-werepoofs. Judgement and my Priest character and even Isaac the freaking Ghoul has anti-evil weaponry and spells. 
[/quote]

Obvious. 

Just think about how many people like anti-heroes over goody-toe shoes good guys like superman. (Skalla is the only person I know with a absurdly good hero character.) 

Also, humans are naturally despicable creatures and relate more with bad guys generally. (cause their [i]cooler[/i], like Scorpion, Wolverine, Blade, etc or batman to the misguided)