3) FERRO LAD

The menace of the Sun-Eater was so grave that the Legion Of Super-Heroes assembled the galaxy’s worst villains to oppose it, but even that desperate gambit (which actually backfired, resulting in the formation of the Fatal Five) wasn’t enough to stop the creature.  Superboy was prepared to deliver a bomb into the creature’s cosmic heart in a final desperate Hail Mary, performing his own Ultimate Sacrifice™ (he is a Superman, after all, and we’ve already discussed their penchant for saving others at the cost of their own life) but one of the newest Legionnaires, a young man named Andrew Nolan, stepped in to take his place.  Ferro Lad not only saved the 30th Century, he avoided a time paradox and defended the legacy of Kal-El, thereby saving billions more in making sure his fellow hero grew up to become Superman…