Are those Tumul runes guaranteed drops or something?

[Fried Noodles]

I found one of those giant head crab monster things in Umbral, along the path leading to Lower Calrath.

When I killed it, it dropped a bunch of loot including the rune that gives you slight health regen when equipped to a shield.

As I'd just placed a temporary vestige literally around the corner from the thing, I decided to kill it a few more times to see if I could get a nice full set of those runes.

Ended up getting two more on my next two kills.

Unfortunately I lack a shield that has an INF slot. And I lack the ability to slot in more than one rune at a time.

But EVENTUALLY I will have Wolverine healing factor.

[Baron01]

Mendacious Visager, that walking stone head, drop Tumul and vestige seeds very often. That particular area with a bonefire in the middle and patrolling Ruiner is great for farming for some loot, runes and seeds. Unfortunately, only temporary vestige is nearby so once you move away from this spot you will have to re-clear back to it and use seed again.