I'm not 100% sure it spawns there
#Obtaining Heart of the Guardian
knotty swift
Of course you could just be extremely unlucky
It doesn't spawn in Ocean Temples...
left stag
6 temples would mean 6-18 elder guardians which each elder guardian rolling on a table of 4 (maybe even 6) items.
The amount of temples is not really expressive but the amount of elder guardans slayn is.
Even then you could have just gotten the other drops each time.
knotty swift
If possible, try getting some more Looting?
plain osprey
Looting unfortunately won't help with getting the heart
left stag
If possible, try getting some more Looting?
it is a 100% chance to drop 1 item out of 4/6
knotty swift
Ah
I never felt like getting the HotGu so I totally forgot it was seperate from the other HotGo so this is news to me.
wanton jungle
Yeah, you just need to slay more guardians
It drops eventually
Either that or something bugged out...
Great to know! 
Actually lemme check what are the odds
Think it's 20%
Or 1/5th per Guardian
6 temples shoulda been way enough, given that these contained, like, 18 guardians....
Misfortune happens I guess
However, I should probably make it more obvious where some items come from, now that I think about it
Because sometimes people may get lost like you did, as to whether they are supposed to just try more, or they need to look elsewhere entirely
left stag
6 temples shoulda been way enough, given that these contained, like, 18 guardian...
up to 18. not all temples generate with all 3 guardians.
so its between 6 and 18. Further you would need to kill 21 elder guardians to have obtained the item within a probability of 99%
plain osprey
I mean, if they're not generating with all 3 then something in the temple generation bugged out