You need the point from batling in war mode to unlock stuff you can buy at war mode shop, after you reach certain point they will be unlocked and you can bought them with gold
Min/max training is the key to make strong unit, try to read this topic http://www.gamefaqs.com/boards/625927-grand-knights-history/60311896
By doing that, you can equip high tier equipment for your low lv unit as the requirement to equip stuff is based on stat, not lv, and its should be more than enough to beat npc team at offline war mode
Where is heaven? Above the sky, and below your feet.