Monster Mash: Where to Draw the Line?

I've played RPGs for a long time and as such have seen my fair share of 'monster mashes.' That is to say, taking two creatures and combining them into one. From the early days of the Owlbear to half-elves, half-dragons and 'Squarks,' combining creatures is a staple in the fantasy genre. That's why I was surprised when I found myself frustrated while working on a high power NPC for our current campaign.

Who in their right mind thought this was a good idea?  

I don't want to spoil it for my players, but I'll let a tidbit slip. I was working on a vampire. An extraordinarily long lived vampire who -for the most part- isn't that bad of a guy. He rules a small kingdom, treats his subjects well, governs fairly and provides for the poor.

He also happens to drink the blood and kill any criminals who are caught within his territory.

I'll leave the 'nature of evil' topic for another post, but I just wanted to set it straight: No matter how much good he does, no matter how fair and benevolent he is, he is still an undead abomination who maintains his (un)life by feeding on sentient living beings. Because of these actions, he is an evil creature.  But I digress...

 Apparently, Roger Corman did!

While researching vampires I came across this thread on the paizo boards. To sum it up, a PC was interested in playing a dhampir paladin/sorcerer with the sanguine bloodline. For those not in the know, that roughly translates to (deep breath!): A half human / half vampire who fights for the glory of god (and/or cause of good in general) who supplements his holy blessings with the ability to spontaneously cast arcane magical spells. Additionally, through his vampiric bloodline, he would be able to consume the blood of the recently deceased as a means to regain lost hit points.

Woo! that's a lot!

That thread, and the flurry of responses it received got me thinking about how muddled up rules and ideas can become with so much monster mashing. I am fully aware that the dhampir is not unique to RPGs and can be found in everything from old Balkan folklore to modern pop culture. Regular fiction is not the same as a game though, and needs no in-depth explanations. Unfortunately, players often do want explanations which for the most part, I am happy to provide.

Although to be honest, I have no explanation for dhampirs in our game world - because they don't exist. As I graphically explained to a PC today, vampires are not living things and as such, don't have much 'fruit in the loins' and as such, couldn't procreate.

What I'm getting at here is, has the monster mash become too much of a crutch for the game community? Should it be viewed as legitimate content or just filler for books and supplements? I understand that gaming companies are businesses and need to keep pumping out products, but do we really need a Monster Manual XXV? Or would companies be better off expanding on actual content, exploring game theory and when publishing monster books, emphasizing quality over quantity?

I do realize that this is nitpicking on my part, but it is still something that gets my goat. Here's a question for the Game and Dungeon Masters out there: Out of all of your 'monster books' what percentage of monsters have you actually used, and what are your thoughts on monster-monster hybrids?

Until next time, happy gaming!