To be honest, the only part of this request that I understood was 'Illya demands a mecha' so I'm just going with that. Apologies in advance.
Requested by: aliesterus
Current Client: Illyasviel von Einzbern Part II
Irisviel: You'd think, after a while, she'd run out of things to complain about.
Illya: Mother!
Irisviel: Hello to you too. Goodness, I'd like to think I raised you to have better manners than that.
Illya: Hi. I want a mecha.
Irisviel:... What?
Illya: A mecha.
Irisviel: A what?
Illya: A mecha! You know, a big giant robot that you can stomp around in?
Irisviel: And why, pray tell, do you want a mecha, of all things?
Illya: It's fun stomping on things. Just like in the Holy Grail Grand Prix! Throwing your weight around always works!
Irisviel: Wait, the Holy Grail what!? All right, that's it. I don't mind you fighting in an extremely violent and hopeless battle such as the Holy Grail War. But I draw the line at racing!
Illya: But Mother –
Irisviel: And besides, isn't your Servant essentially a big giant man who stomps around? You've already got a living mecha, technically speaking, not to mention I've told you again and again it is NOT all right to destroy other people's property. When will you ever learn?
Illya: But the mecha might help me in the war!
Irisviel: I don't care! War or no war, it's time you learned a few lessons! The younger generation these days, honestly! Always demanding everything and expecting everything to be handed to them on silver platters. Anything from video games and sweetheart photos to magical barriers and mechas! What next!?
Illya: The mecha... calls me...
Irisviel: Nothing doing, sweetie. I think you've got enough things to doo, what with that huge castle of yours. I'm sure you'll find something else to entertain yourself with. Now be a good girl and go play and let Mommy work.
Illya: I'll get a mecha one way or another! You won't stop me!
Irisviel: You watch too much anime.