DouKaku?

:: capitalize.bat
@echo off
  setlocal enabledelayedexpansion
    set c=
    set t=
    set w=

    if "%~1" equ "" (echo %~n0 [STRING] & exit /b 1)

    for %%w in (%~1) do (
      set w=%%w
      call :upper !w:~0,1! c
      set t=!t! !c!!w:~1!
    )
  endlocal & echo %t:~1%
goto :EOF

:upper
  setlocal
    set t=%~1

    set t=%t:a=A%
    set t=%t:b=B%
    set t=%t:c=C%
    set t=%t:d=D%
    set t=%t:e=E%
    set t=%t:f=F%
    set t=%t:g=G%
    set t=%t:h=H%
    set t=%t:i=I%
    set t=%t:j=J%
    set t=%t:k=K%
    set t=%t:l=L%
    set t=%t:m=M%
    set t=%t:n=N%
    set t=%t:o=O%
    set t=%t:p=P%
    set t=%t:q=Q%
    set t=%t:r=R%
    set t=%t:s=S%
    set t=%t:t=T%
    set t=%t:u=U%
    set t=%t:v=V%
    set t=%t:w=W%
    set t=%t:x=X%
    set t=%t:y=Y%
    set t=%t:z=Z%

  endlocal & set %2=%t%
goto :EOF