So trick master says
"you may put and number of fire type magic cards from your hand on this card during your action phase. (this does not count as a play) this card gets +X pow, where X is the sum of all damage amounts of magic cards STORED on this card."
If my interpretation is correct, you can play the magic cards on him any turn you like, as in they don't need to be played on him when he is, AND that those cards stay on him until he is discarded.
That's not bad to have a growing dark card out.... and if he's on a fire world that damage doubles.... nice!
Get back to me to please verify this, thank you
Zarathura