>>535625250
Dioscuri is cool for blending their arts and quick cards together but they hit like a bowl of noodles
Otherwise it's because extras rarely have class advantage so they want to put spice into it. On the flipside if they want to put spice into a servant making them one of the main classes might make them too strong so they toss them into an extra class. I doubt Foreigner was the first class they thought of for Aoko