Bastian is a storied Pokémon indeed, having a hand in saving the world several times and being associated with alot of prestigious guilds, including his own. Thing is, he's had to struggle alot to get there. From the outset, he was once the human counterpart to a Pokémon of the same name, a valiant Lucario from the future who was, unfortunately, killed while resisting the influence of Primal Dialga.

Brought into the Pokémon World, he was flung into the efforts to save the future, but was subsequently strung along a series of unfortunate events that lead him to joining the illustrious Pukurin Guild... and erasing himself from existence.

Of course that isn't permanent, but almost immediately having been brought back a year later, he then had to save the world again from Darkrai. Ontop of that, he had to deal with the unwanted relationship with one Charm Sukebenaon'na, and well, that had long lasting effects of its own...

That's not everything, not even close, but it's an important display of just how much Bastian has suffered ever since he became a Pokémon. Despite all of this suffering, Bastian is a dutiful leader and a dedicated explorer, though a tortured one. Guild Eterna is built upon his backbone afterall.