I got through the first 3 quests pretty easy, not even knowing how to do them. This last one stumped all of us though. I am pretty sure I have to complete a map on my own like fael. Let's hope its something other than ZOMBIES!
Striker quest 1: This one if I can remember correctly was 70% style or Technic on any map. Not hard when you have Ash in the party AM I RITE?
Striker quest 2: This one was the same as the first quest, but I think you have to be on a certain map. We loved killing that bull on the easy maps. Most of my quests were attained from doing this map or the fire queen.
Striker quest 3: This map was collecting 7 quest items. I am still not sure what I had when I completed this quest because I was an idiot and didn't screen them, but I do remember I completed it during the bull map.
Striker quest 4: Final quest which I have just found out for myself, complete the Mage type monster on expert mode. This is the map over the dragon boss on the Sky castle stage.