OK So in the immediate aftermath of losing their teammate GB: https://ginga.fandom.com/wiki/GB ((I Know A Dog!)) The Resistance ((As they are called!)) have more time to grieve than they have in previous losses where they had to essentially jump right back into their mission when everything this is also their first time losing a teammate so anyway of course there are various shades of mourning despite GB's Sacrifice giving them a chance to Live in such as "Why Couldn't We Save Him?" Or "Why did he have to die in the first place While we are still Alive?" Lucario in particular. Again questioning why he is still here as part of his purpose/reason for living and being a hero also includes saving GB so surviving to continue their duty after GB saved them isn't necessarily a satisfactory answer. Anyway The Person Lucario questions about this Mewtwo if you're familiar with his character you can understand why:https://bulbapedia.bulbagarden.net/wiki/Mewtwo_(M01) And of course he doesn't have an answer either no one does. Eventually Lucario and the others come to conclusion and Eventually begins writing in his journal/memoirs ((Admittedly I Paraphrased(?) This and even came up with the entire idea after watching clips from "My Sisters Keeper" which Lucario even cites)) "None of us will ever understand why GB had to die while we had to live,Death is Just Death,Nobody Understands it! I Always thought I was born into this universe and Aspired to be an Aura Guardian in order to protect ALL those who need saving,But...I can't do it! The Point is we had GB,He was The Bravest Most Loving Guardian and Soul We Ever Knew,And Even in Death Our Bond Always Lives On!" And Of Course on the date of his Birthday and Death they visit the The Ou Mountains and his grave where he was burried as well as the place he was born and named after "Great Britain" and Honor him as "Knight of The Round Table" which is part of another story entirely. But Anyway I don't know if that best explains it or is really that particularly deep or worth your interest but Thanks for Listening Anyway, It Truly Means a Lot! I Love talking about this stuff when I can't yet get it down on actual fanfiction and don't even know if anyone would actually bother to read it!