Geitz is top 5 units in the game and he's locked behind doing the mine glitch, removing all of the enemies weapons on Genesis or the Desert map, getting Eliwood and Lyn both 17 levels, and Hector probably around 5. Along with this you also need to bare in mind that Eliwood cannot damage the enemy and Lyn can double the enemy, to no avail as she also does nothing. This aspect of locking a unit behind such a blasphemous, mind-boggling requirement is beyond me, but it's pretty funny on the game designer's part.