[kitten320]

Spoiler for ending:

Lol wish you luck to collect the courage




Their purpose was not destroy Inferno here. If that was his aim, we would have different story here.
At first they did fight in order to live but afterwards the only thing Reiji aimed for was to fullifil at least one promise.
And he did that. He was happy in the last moments of his life so basicly he had served his purpose.

I can't say that I 100% like the ending, I also would have prefered slightly different one. But I simply don't see all the horror as some of you make.