Polarity Duo and their relationship with death, warning: long ramble
The fear of death is (unsurprisingly) a very common phobia, for those who care about phobia names its called thanatophobia. But i won't be calling it that here. But it needs to be mentioned that thanatophobia includes both death of oneself and of other people. This will be important in addressing Saps and Flux
One point of their example in being the opposite of one another is their thoughts to death. Flux is afraid of it, he would like to be immortal if he was granted any superpower, he doesn't want to die.
Even if it means leaving behind his loved ones and everything he knows, because being immortal means you will literally out live everything anf everyone; usually media tends to portray it as a curse. But flux doesn't. I think flux is putting more nuance to this choice by not telling the full reason as to why (or i might be reaching and just finding reason who knows honestly)
At first i thought it might be caused by a near death situation he experienced in the past. But after further consideration, i think there is more to it. One of the biggest fears people usually have is the unkown of death or the unclarity of it, you don't know when, where, or how you're going to die, and that uncertainty can cause paranoia to bloom within an anxious person — obviously not everyone is like this, there are people that simply do not care and those who makes the most of their life with that indefinite time.
But for someone who has an anxiety problem, that is one less issue to worry about. Because if you are immortal, you don't have to think about how you'll survive the next day, or if your death is going to be unexpected, or how much pain you'll be or the hows, whens, where, or what causes your death. If you are immortal, you won't have an inexplicable death. Instead, your death will be in your hands. That paranoia of uncertainty is gone (this is me assuming the immortality that flux is talking about is where he can still die by killing himself and not like...constantly being brought back to life)
And that leads us to saps.
Now saps is interesting, just like flux, he is ALSO afraid of death. Its one of his biggest phobia even. But unlike flux, he doesn't want to be immortal. He doesn't want to keep living for years and years. He doesn't want to outlive his loved ones. He wants to grow old with them, watch as time flows by and have a death where there will be someone who misses him
And that's when i realized. Their fears are of 2 different types. Flux fears the unknown of death, the loss of control —unable to stop or manage the process of dying— and the possible pain. He fears himself dying.
Saps on the otherhand, he knows death is a part of life, he accepts it, he knows he's going to die and he doesn't even mind cutting his life shorter, just so he doesn't see some people in his life die. He doesn't fear himself dying. He fears other people dying; more specifically his loved ones.
One to take note of is that saps is a very loving person, he cares about the people in his life and he cares about how they feel. Its another reason why although it is intriguing that he seems to understand suicidal idealization and can seem to play those characters well, he himself isn't. Because he doesn't have the heart to be the reason for the ripple effect of what his actions can cause (his loved ones following suit); worrying about how they'll cope and feel after he's gone
Its honestly something i find interesting about their contrast, Saps has a lot of people in his life that he cares about to the point it prevents him from wanting to even consider hurting them that way, which leads to him fearing for their deaths instead (and also his own since it carves the uncertainty of how his loved ones will cope). Now i don't know flux as well, but from what I've been informed, he doesn't really have that great of a relationship with people irl in his life (feel free to correct me), which leads the fear directly to himself
To put it in simple terms, both of them fear death but of different aspects of it. Saps more so thinks of other people, while flux doesn't