Can I use this [On Block] effect to play a Character card from my hand if I have 5 Characters in my Character area?
Yes, you can.<br>In that case, you will reveal the Character card that you will play, trash 1 of the Characters in your Character area, and then play your selected Character card.
I declared my attack while my opponent had 5 Characters on their field, and my opponent activated the [Blocker] of "OP01-014 Jinbe".<br>At this time, my opponent chose to play a red Character with a cost of 2 or less from their hand according to the [On Block] effect of "OP01-014 Jinbe", and trashed the Jinbe whose [Blocker] they had activated according to the rules.<br>In this case, will my Character become active?
No, your Character will not become active.<br>Since the target for the attack no longer exists, the Counter Step and Damage Step will be skipped, and the battle will end. In this case, the requirement that "this Character battles your opponent's Character" is not resolved, so your Character cannot be set to active.
