I enjoy the idea of death not being the end of a character and their part in the story. At least once so far in my first novel someone dies and continues to exist beyond the void, in the spirit world- but she is a special case.

While writing the second novel there are two characters who:

1) has something so powerful and valuable that he would rather blow himself up than to let certain bad guy get it- and certain bad guy must get it in this book to develop the series, but i also dont see any other reaction this guy will have other than " screw you we are both going boom." The problem is he is one of the favorites of book 1, everyone who has read it loves him and I feel so bad for wanting to kill him almost a quarter way though book 2. Hes a scientist, and studies consciousness and has experience cloning- is it too far fetched that he has a clone or android type thing in the background of one of his lairs ready to have his conciousnes uploaded into? As a spoiler, he does manage to build himself a conscious robotic "wife" so who's to say he cant have a back up in case he dies?

2) One of my secondary characters, someone who spends a whole bunch of time with my Mc and is far too important to straight up kills, end up in a dire situation. I can either have her end up existing in the spirit world, but then i dont want this to turn into Dragon Ball Z where everyone who dies can be brought back. Essentially she ends up wearing a crystaline necklace that embeds itself into her and crystals start spawning all over her skin, she becomes corrupted, and controlled by the sin/entity that specific crystal reresents. My MC fights that entity and in the process rips the crystal out of her friends chest to try and save her, which would most likley kill the poor girl.

Her job, while being controleld, is to lure children into this demons lair where they feed off their innocence and essence, all the children are absorbed into a crystaline wall and just left there while little beads of light drift off and feed the demon. After the demon leaves, is it too cheesy to have these kids energy- who are technically dead absorb into wounded character to heal her?

I guess I'm just trying to find ways to kill people without killing them, or if anyone has any sugestions on how we can magically bring people back after they legitimatly die I am wide open

.Edit: More specifically how would you go about bringing someone back after they tired, through magical, technological, spiritual means or otherwise?