This VERY DIFFICULT mission was done on NORMAL Difficulty and POST-GAME (i.e Final chapter weapons).
I had already cleared it once for the Ace's weapon. I do use a special DLC sniper weapon that kills the tank in one shot, but it is not necessary as you can just use your tank. I just used it to save CP as some of those enemies dodged my attacks "unfairly" earlier. ;-)
Ruhm is also NOT necessary if you have a good machine gun and equip either an extended range or golden bullet accessory. You do need 2 or 3 good snipers and a 3rd level *Valkyria* scout and one 3rd level Engineer at the start of the level (to help with taking the first base more easily).
Stage Name: 国境のヴァルキュリア
Map Area: ランシール士官学校
Difficulty: ★★★★★
S rank: 4 Turns
Goal: Kill all Units (敵ユニットの全滅)
Ace Name:千人狩りマシター
Ace Drop: ゲルA（ピストル）
ゲルA（ピストル）STATS:
CLASS: Engineer Pistol
vs Personnel 61
vs Armor 57
Aim 70
Range 150
Shots 6
Suppression - C Rating
Status Affliction - Defense Down
