I'm now working on a Pokemon that will not only replace most of the good, functioning roles Lucario has served, but perhaps do them even better, all while also offering team support. I'll leave this Pokemon secret for the time being, as I don't want to reveal everything about my team. But I'll tell you this - even though I don't even have the species of Pokemon yet, it's going to be one heck of a doozy on the battlefield. If only it had a little more Speed, it would be monsterous...
Lucario is a boosting sweeper.
From the information, we can tell that it is a boosting sweeper, a support Pokemon, and is a legendary Pokemon with seven letters.
This leaves Suicune and Jirachi.
Jirachi fits the description perfectly since it can support teammates as well as boost and sweep. It is even legendary and has seven letters! He also admits that he doesn't have certain legendaries, so...
watch him tear his hair out IF i get it right. if not, then it is most likely suicune. 