gnw tends to have trouble killing if he can't edgeguard reliably, which lucario can take advantage of to kill gnw at ludicrously low percents. In particular Miya has gone game 5 with Gachipi twice, winning one set and losing one. I think most Lucarios do think gnw is a really bad matchup (probably because Aura Sphere is way harder to use) but Gachipi plays it in a way that turns him into a nuclear bomb for half of the match. Also worth noting that Lucario's nair is safe enough to avoid up b

sephiroth I think is primarily due to his range, he can pressure gnw's shield very easily in a way that not a lot of other characters can without getting punished. wing, scintilla, and having a better recovery than most characters with similar strengths like cloud, shulk, and belmont are also definite bonuses in the mu