You were last in here a few minutes ago, but you particularly remember having to run from panel to panel just to get a clear picture about what went on here over 16 years ago. That's when it'd have to be, because that's how old the person you call your sis is. Now, based on the knowledge learned here, today, you don't know how old your "original" sis was. She probably was about 20 when she started doing the experiments, and from what you can tell, the experiments ran for at least a year, based on the number of clones you suspect to have been made. So that puts her at about 21 by the time she kills herself, maybe a year or two older. That's pretty young for somebody to just go out like that. Your only notion of to why is that she needed to do something, but that something is basically non-existent in your mind.
You are an avid life-enjoyer. You have been for almost all your life. It basically started when you first learnt of the story of the 7 souls. After you learnt of this, you were quite adamant that no life shall be extinguished for almost all purposes. The only other one you can think of is for food, as much as you like life, fish definitely tastes a bit better when caught fresh in the wild. When Suki threatens to kill herself, you try so hard to coax her away from self-harm and into a better place. That's why you have a no-nonsense policy when it comes to suicide threats. You personally feel obligated to help out. Why you feel obligated, you have no idea, just that you do.
You don't like the idea of killing oneself, but if it's absolutely necessary, you could suppose it's fine. Such as maybe someone threatens the entire world unless you kill yourself. But this is extremely unlikely, and won't ever come up again...