Greedling's introduction is actually really funny because Greed does the typical evil possession rant about "your friend's gone I'm the only one left!" and Ed looks into his eyes midfight and is like "I know Ling's still in there" and it seems like the set up to some long epic struggle where Ed will have to reach out to Ling to prove he's still alive and help him overpower Greed

And then maybe two hours later Greed tracks Ed and Al down like "hey I have a message from Ling could you give it to Lan Fan for us? No clue what it says but that's probably fine. anyway don't try to foil our evil plans! or do I don't actually give a shit. later losers."