elixir, 209 bytes

Result

AC

Duration

1851ms

Code [DL]

defmodule F do
def f(s,x,t)do
case IO.gets x do
:eof->IO.write String.slice String.trim_trailing(t)<>String.duplicate("*",99),0,String.length String.trim_trailing s
t->f s,s,t
end
end
end
F.f IO.gets(""),"",""

stdin

                             T                    
                                                  
                                                  
                                                  
          K                                       

stdout

                             T                    
                             T                    
                             T                    
                             T                    
          K*******************

stderr

strace