Return of Reckoning

Hello gits! Im looking for a spear for my Squig Herder but i cant figure out where this/these weapons are from or if they are still available ingame the name of the weapon is: Stabba of the Patient One, Warworn Stabba, Antediluvian Stabba, Stabba of the Sandstorm and they all share the same appearance.

Links to the weapons:

https://killboard.returnofreckoning.com/item/662195
https://killboard.returnofreckoning.com/item/666195
https://killboard.returnofreckoning.com/item/901226
https://killboard.returnofreckoning.com/item/2001795

Any help/confrimation is appreciated!

I think they are dropped from some monsters,like this https://killboard.returnofreckoning.com/item/10555 It can be found on a boss in the bastion stair