they were just kids
ive decided to change a few things about instability and romsir's relationship. the biggest two changes are that instability was originally mortal, and he and romsir have known each other since the beginning.
instability is a breath, one of the sapient fundamental concepts that shape the world. the first entities born into the ether were breaths, but some mortals were born before the final breath was. instability was the first mortal, and he was mistaken for a breath and raised as a god. he does know he's mortal and treats other mortal souls as younger siblings.
romsir was one of the earliest mortal souls after instability, and they lived in the first universe. when the first universe collapsed, they were one of the only souls that wasn't destroyed. instability became protective over them and helped guide them to the second universe, and then the third when they were killed again, and so on until present day.
instability acts like romsir's patron god in a way; when they're killed, he comes running to protect them and help them find their way to a new life. because of his false godhood, instability struggles to actually protect romsir in the mortal plane and they rarely live past 40. romsir doesnt hold it against him.
also small tidbit, all the oldest souls look like dogs regardless of whether theyre mortal or a breath. its a holdover from the Beginning actually still being alive while these new souls were being born. mortal souls are also generally not supposed to live more than one life, theyre too fragile and unstable to stick around in the open ether outside of a universe for very long and quickly fade back into the mesh they rose from. romsir is one of many fringe cases that is outliving their scheduled death as a result of the death of the breath of senesence.