Highly Notorious Monsters

[Alerith]

Close I give you credit for a good idea but not quite with that method though. Imagine killing 9 buffalos how's it gonna know you are there to "spawn" the oversouled one. What about if you are on your 10th Ifrit but I've only killed it twice...

Maybe a personal increase in drop rate for the same mob if its your "oversoul" kill. Hard to see it happening on roaming world NMs/HNMs.

Well, there could always be a simple prompt.

"Claws reach from the afterlife as if you grab your soul..."
"Face the Oversoul Buffalo?"
Yes< No

-You are now bound by Duty-
You're taken to an instance for the Oversoul fight.

Your 10th buffalo kill could cause a (!) to appear on your minimap NEAR his usual location that you can use to initiate the duty.

For Ifrit (or other BCNMs), it's a bit easier. You would simply have to be the one who takes the party in. Check the aether:

Bowl of Embers (Hard)
Bowl of Embers (Oversoul)<

[XStruckX]

Well, there could always be a simple prompt.

"Claws reach from the afterlife as if you grab your soul..."
"Face the Oversoul Buffalo?"
Yes< No

-You are now bound by Duty-
You're taken to an instance for the Oversoul fight.

Your 10th buffalo kill could cause a (!) to appear on your minimap NEAR his usual location that you can use to initiate the duty.

For Ifrit (or other BCNMs), it's a bit easier. You would simply have to be the one who takes the party in. Check the aether:

Bowl of Embers (Hard)
Bowl of Embers (Oversoul)<

As much as it sounds like a good idea, it also kinda just says "redundant"

Its like trying to fix a small leak with 100 tons of cement. It's not really needed and it could start a brand new thread with new problems.