If Valvatorez is lvl. 500+ you get the god ending, which is the only different ending.
The epilogues are the ones that are really changeable, and requires the use of the legendary tree.
Here is a short guide for each one:
Vulcanus?( Artina ) epilogue: default
Fuka: Have her relationship with Valvatorez be Mentor and extra gain from her 10 times
Fenrich: Have him as Comrade and team attack 10 times
Desco: Have her as Stepsibling and protect her 10 times
Emizel: Have him as Rival and attack him 10 times
"Is it pre-battle nerves or are you suffering from a calcium deficency. Either way the answer is eating sardines"- Valvatorez