Looking for interesting ways to stop regeneration

[Third Mind]

Ok. So. Let me start by saying that this is for a custom vampire template I'm slowly working on and that I do understand that the most common ways to stop regeneration are fire and acid. That said, I'm looking for unique and interesting ways to stop this particular vampire's regeneration.

This particular vampire is meant to be one that torments and hunts other types of vampires. His regeneration is his primary defensive ability, and is largely what keeps him alive (currently pondering other unique ways for the vampire to be hard to kill, or stay killed). That being the case, I'm looking for the way to stop the regeneration to be somewhat (but not completely) hard to find / get, and maybe even a bit obscure.

Some of my current ideas would be:

The ashes of the vampires loved one.

The bone of the vampires loved one.

One of the more uncommon types of material, such as living steel or Void glass.

A filled soul gem.

Any other cool suggestions you all might have for this? Also, any other neat ways for it to be hard to kill or come back would be welcomed as well.

[Val'bryn2]

Just to make it harder for the enemy vampires? Bypassed by Good weapons. Since the weapons burn the vampires, since they are evil, they are unlikely to wield them. You could make it that, for the custom vampire to be vanquished forever, his remains would have to be sprinkled with the ashes of a vampire who chose to meet the sun.

[Third Mind]

I like both of those ideas, especially the ashes of a sun killed vampire. Holy weapon works, although all they'd need to do is hire a neutral or good person to attack this one. But that's not any less difficult than the ideas I've thought of thus far.

Thanks.

[Havoq]

Woundweal, or invent a concoction that includes it.

[Goth Guru]

They regenerate all damage except damage made by wooden weapons. For that they need to drink the blood of a vampire.

[jhansonxi]

An adamantine golem has to be reduced to 0 HP and decapitated with an adamantine vorpal weapon. Maybe something like that.

[Scythia]

You already covered something similar to what I was thinking: bone of a blood relative.

There's also the classic: damage inflicted by a dhampir. (Only the half dead can hurt the undead)

If you want to give older gamers a moment of joy, consider electrum. The purity of silver alloyed with the golden colour of sunlight.

[Goth Guru]

Half vampires should be vulnerable to electrum.

[Lincoln Hills]

In Stoker's lore, a vampire retained a contagious-magic connection with its original grave. Something like that could be used: the regeneration is stopped not by anything done to the cannibal-vampire itself, but by opening its grave to sunlight. No matter where the vampire is at that time, it suddenly loses its regen (or may be forced into gaseous form, or whatever). Staying alive until dawn then becomes a necessary 'step one'. As an added bonus, a weakness like this will require the PCs to explain to the highly skeptical locals that "we're not robbing this grave in broad daylight, honest."

[The Indescribable]

The grave thing is awesome.

[kyrt-ryder]

Mother f!@~ing sunlight.

Just pile on the damage until it can't regain consciousness before the sun comes up and GTFO.