Not sure if this has been done yet but a name search has revealed the following:

Death: 63

Pestilence: 55

Famine: 43

War: 31

Assuming these Kami are not released again in the future, War will certainly remain the rarest. According to a poll in this thread, Famine is the most popular, followed by Death.

Cheers!

 Edit: Whoops, someone counted them up before I did! Thanks Peace123!

 Peace123 also points out that 29 players were able to obtain all four Kami.

Note: If you search for Death/Famine etc. as I did, be aware that pets may be named Death that aren't Kami. I checked all name links, so my values should be pretty close. Here are the rest of the pets, for funsies :)

Non-Kami pets named Death: 15

Non-Kami pets named War: 5

Non-Kami pets named Famine: 3

Non-Kami pets named Pestilence: 0 (Not the most popular name I guess)

Thanks for taking the time to count these out, I was actually interested in these numbers, too :)

These ratios of the Kami are actually around what I had anticipated, but it's still interesting to see how many people managed to do it :)

Yup, and I'm very glad to have all four ^^

Actually 4 is the ideal four a squad :D

I wasn't surprised at War and Famine being the rarest, having the battlefield requirements. Since the requirements for the two seemed comparable in difficulty, I assume the difference lay in popularity (Famine was the most popular while War was the least).

Something did surprise me, though. At the beginning of the even I calculated how many War/Famine Kami could technically be caught in the course of two weeks:

(1 Kami/10 hours)(24 hours/1 day)(7 days/1 week) = 33.6 = 33 Kami/week

During two weeks, the number of War/Famine Kami that could have been caught was (33.6)*2=67.2=67 Kami.

Not even 50% of War Kami were caught!

I thought Famine would have been easier for people as it mostly needed food, which you can get in three days maximum pretty much... But I guess the Crimson tree held people back.

When I first saw the requirements for Death I thought it was the perfect time to do some stable clearing, and I bred some pets as well.

I am surprised how popular Pestilence was- as the cockatrices were tricky to come by. It was by the good graces of people on here that I was able to loan a pet for it. o.0

Very cool info though!

Aye, War was definitely harder for people since they actually needed Squads that could defeat others and that 20 times.. In comparison the food was easy to do. So it makes sense that more Famine are around than War. Nightingale is right, the Crimson Tree held people back - especially those that don't frequent the Forums. They wouldn't have known about the possibility to get the Tree (relatively) easily. 

And mosaic, actually not even 25% of War Kami were caught. You're forgetting Mirror world. Means 2 Kami per 10 hours would have been (theoretically) possible. 

Also towards the end, I saw loads of Venom Jars in the Item Exchange, since many (like me) did the quests every day and then sold or gave the excess venom to those still in need. I think that's where a lot of Pestilence came from. 

Thanks Timain! You're right, I completely forgot the mirror world. The total possible War/Famine Kami that could have been caught was (67*2)=137.

I also forgot the squad requirement for War, so the discrepancy makes much more sense.

Really interesting to see this. I suspected War would be the rarest because it had two battlefield requirements while Famine only had one, so it makes sense to me that there are a few more Famines out there than Wars. I had no idea that the discrepency was that large, though. And only 29 people with all four kami? That's...not very many. If the site takes off in popularity in the future and these don't get re-released, they are going to be ultra-crazy-rare down the road.

Yup. I get the impression that Kami are supposed to be the super-ultra-crazy-rare pets of BK...I wonder if that's why they were released so early on? 'Cause I'll be honest, such a high-level event so early in the game doesn't make much sense otherwise.

Dang... But I couldn't bear to part with mine! Together they make the four horseman! Hahah.

Hmm, maybe the apocolyspe should have happened after all?

Well now that you guys mention it, now I'm getting the impression too. XD Unless there's a series of Kami events down the road ( You know like themes?), then yeah I think at least a handful of us just managed to snag some " Super-Ultra-Crazy-Rare" pets. :) Maybe it's something to give more longtime users a treat, since this game is definitely taking off with more and more users every day? 

I didn't realize so few people got all 4! -snuggles my four Kami- I couldn't bear to part with them either! Ironically, War is my favorite even though he is the least popular.

I got 3/4, but that's because i didn't wanted to part with my Vermillion and rake up 20 wins.

Oh lol thanks mosaic! Im so surprise that only that many people got each of those Kamis. :)

The vermillion was the hard part, since it's so hard to gather and there was none to be found for a reasonable price in the item trades.  I waited to get the essences of war until I was sure I really wanted to sacrifice the vermillion.