Besides the fact that id Software created both the Commander Keen and
Wolfenstein games, there is a further relationship between the two main
characters.  The following is an excerpt from the Official Hint Manual for
Wolfenstein 3D which explains the relation:

      William Joseph Blazkowicz was born August 15, 1911, to Polish
      immigrants.  Blazkowicz was a top spy for the Allied Forces,
      receiving the Congressional Medal of Honor and other accolades
      for heroism.  "B.J.," (as he was called by his friends) married
      after World War II, at age 40, to Julia Marie Peterson.  Their
      son, Arthur Kenneth Blazkowicz, became a television talk show
      personality in Milwaukee.  For show biz purposes, Arthur changed
      his last name to Blaze.  Arthur later married Susan Elizabeth
      McMichaels.  They had one son (which they named after Arthur's
      father), William Joseph Blazkowicz II, or as he signs his grade
      school homework, B. Blaze....