Q45. Are any of your OCs dead, planned to die, or have been dead at any point (even if only briefly)?
oh goodness yes
First and foremost, all of the Tested have died at least once. These characters were involved in something called the Competition, which was essentially a fight to the death where whoever dies last gets to become a higher being. But, no biggie! They were created by said higher beings and are pretty close to them, all things considered, so coming back to life is no big deal - not that any of them knew they'd get to come back to life until it happened but, hey, better late than never! Whenever I use them for RPing or anything, it's always after the end of the Competition, so they've all died at least once. Seraye's died twice, since to make a long story short she died before she managed to get suckered into being part of the Competition.
In story canon there are a bunch of way less serious Competitions afterward (some of which involve more dying), and in RP canon I've RPed, like, 7 other Competitions that have more gravity to them because they involve other people's characters - people who aren't pals with a bunch of gods and are very far from home. In both, the implication of the Tested's effective immortality at the hands of someone who does as she pleases with them is a strong theme.
Dicro (and by extension 2cro) gets special attention here because he dies pretty much constantly. Dicro has the ability to physically travel on the subconscious plane, which is a pretty dangerous place. It's not that big of a deal, though, because aside from the whole Tested-being-chummy-with-higher-beings thing Dicro happens to be particularly close to who is essentially Death. Even outside of the dream world it's a running gag that he dies on a regular basis, but he doesn't really mind it.
Hadris has 'died' a few times, as he often serves as the "final boss" of various different epic adventures across Entirety. Good always triumphs (unless you forgot to grind), and Hadris is a graceful loser who will usually let himself actually die. Of course, he's got an empire to run, so there's a spot in his realm that he can regenerate from under most circumstances. What kind of final boss just stays dead, y'know?
Euphesme is more of a straight example, having died before the story she's in begins. She spends the story as a ghost, haunting her sister (who was the one who killed her). Aedi was originally planned to kill herself in the middle of SYOL for Reasons (the first time I wrote the story she actually did so pretty much right after she was introduced), but the more I developed her character the less sense that made. Her death was really just something to be a Shocking Twist and make the main character doubt things, but her character was just... so much more than that and I couldn't justify her doing something so out of character given the circumstances. So, I retconned that about a year or so ago and for now she's alive the whole time! Hooray!
Finally, the story Alma and Monaz are in is a visual novel, and as such they (and just about every other character) can die if you pick the right choices. Err... wrong choices? You know what I mean.