Board Thread:Questions and Answers/@comment-31067473-20170714200704/@comment-27136653-20170811063455

As I said, they gave up. Either because they were too frustrated to continue (lost their determination), or they gave up their soul willingly. I'm not saying that all of them did it that way or the other. Some quit that way, some (like kindness for example) quit the other way. The humans were strong, not weak. If they were weak, their souls wouldn't be able to shatter the barrier.

And no, it does not render the SLR power obsolete. Chara too had an access to this power, as some evidence suggests (and even if you don't believe that, they still had the same soul as Frisk, so if you believe Frisk is so determined because of their soul, then Chara must have been too). So, if Chara had this power, then why did they die? There is nothing "obsolete" about this power. It simply backs off when the human "agrees" to die.