Orb of unity farming setup?

[Ignis]

Currently at chapter 3, I just want to unlock the river and the alchemist, but this orb is so rare. From the encyclopedia I see that only slimes, swarm of ghost/ bats and blood clots can drop them. Swarm of bats/ ghost is a pain to try to spawn, slime only got 5% chance, and blood clots spawn timer is also long (4 day/ 1 clot). I'm thinking of slimes only run or blood clot only, any ideas?

[Mongooses]

Chrono crystals on for the bloody ground are a great help with blood clots, and more blood clots mean more ghosts. Groves + chrono crystals near battlefields (but don't overwrite the bloody ground) is decent to try and get more ghosts.

From zone 2 onward vampires spawn the bats. Ghouls and vampires also have souls, so another good location for a battlefield to get more ghosts.

Field of blades are also a swarm. You can either destroy the town after placing wheat fields or place the wheat fields next to the "town?" created by placing 10 forest/thickets... and guess what, they have souls too!

Overall it is one of the slower orbs to farm.

[Doombringer]

I get plenty by farming chapter 4 boss, you don't need that many anyways.
(Unlike orb of evolution, you will get more of all the other rare orbs than you need farming orbs of evolution...)