What would be the worst finale for the series?. The possibility of a tragic end.

Watari maybe delay the last volume because he may have a surprise not very pleasant for the fans. What would happen if all this ends in tragedy?. I love sad and tragic endings because I think they have a greater emotional impact and at the same time they are usually unexpected. Could it be that some of the characters are going to commit suicide? Could Hachiman be left alone to not hurt anyone but himself? or maybe Yui go full yadere! that would be interesting to see.