After bonding with Scáthach, she became more and more demanding from you. You weren't so sure why she did so, but when inquiring about it, all she did was bestow you a gift. Gáe Bolg. The very spear she wields, well, at least one of the many she has. You understood what she meant by that; she entrusted you with her deepest, most desperate desire. She wants you to become strong enough to be able to kill her.
From that day onward, she has put you in a very strict training routine. She wants you to surpass Cú Chulainn and become someone that can truly rival her, even though you are just human. When she drags you along the halls of Chaldea, the other Irish Heroic Spirits look at you with pity in their eyes.
After a long sparring session, Scáthach orders you to do push-ups with her sitting on your back.
One... two... three... why are you slowing down, Master? Don't tell me that you're tired after a mere two hours of sparring.
She sighs and gets up.
Guess you need a little motivation.
She excuses herself, leaving the room and coming back shortly after with her bunny costume on. Making a cute pose just for you, she mutters with a serious expression.
Pyon, pyon! Now...
She sits on your back again, adding more weight than usual.
This should keep you motivated. No more excuses! I want 20 reps.