Assuming he's not counting Kid Quantum, I think it's the first Legionnaire killed in the Mask Man story.
I want to say.... Ultra Boy?
The Mask Man story (from Adv 310) is what I was thinking of, and Ultra Boy is the first victim, even as the team still mourns Lightning Lad. Followed by... well... everyone else.
EDE gets next question!
Interested in the Post-Zero Hour Reboot Legion? Check out:
Yeah, I was taking a wild swing with that one. This is (I think) an issue that I don't own (if I do, its buried deep), but DO know exactly to whom you are referring. Unfortunately, the only reference I can find for the answer has an obscured scan, so I don't know what the word says other than "Lad"
Interested in the Post-Zero Hour Reboot Legion? Check out:
I actually had a really hard time viewing that picture, as the first half of the word is a bit fuzzy, at least to me. But I thought I read that as Estimate, but then I couldn't remember hearing about him, ever.
So then I did a search for "Estimate Lad" and found that he had been introduced in the Legion of Substitute Heroes Secret Origins.
So there we go.
Interested in the Post-Zero Hour Reboot Legion? Check out:
Rockhopper Lad: The Rookery Holiday party is in progress! Pop by!
Ann Hebistand: I am so going to attend! Thanks, Rocky!
Nightcrawler: Updated us to version 8.0 of the software. Everything resets to the default settings. I'll be restoring things back to normal as I have time.
Nightcrawler: Sorry. Didn't realize the solution I had for the old PHP would screw up the new board.
Nightcrawler: Our server got moved by our host, so any images that were uploaded today will need to be reuploaded and replaced. Sorry. I think I fixed it now.