Fragarach, Rare, 20g1r
Legend. Rebirth.
Attack: 15
If opponent dealt damage last round
Negate damage dealt
Return resource cost of opponent's last card
Replace matching card with opponent's last card
Attack: N
N = Damage dealt to you last round
I enjoy a challenge! Let's see if I can make this a little shorter...
Legend. Rebirth.
Attack: 15 + N
If N > 0
Negate opponent's last round's damage dealt and card cost
Replace matching card with opponent's last card
N = Damage dealt to you last round
I can't tell if this makes it harder to understand.
At the very least, combining the Attack into one operand and reducing the If as above saves two lines.
Also, should it be worded as opponent's last card rather than last round? Otherwise, won't it be summing the damage of consecutive Quick cards? Or is that intended?