Kingdom Hearts vs Fate
Connection:
Both are teenagers who fight in endless wars of light and darkness being part of great warriors (Keyblade Welders and Servants) with weapons unique to their universes (Keyblade and Noble Phantasm respectively)
Both are considered the higher ups (Aqua being a Keyblade Master and Jeanne being a Ruler Class Servant) but despite their status they are conflicted between their responsibilities and helping friends and comrades
Both are a part of trios with two boys and one girl (Terra & Ventus and Sieg & Astolfo respectively)
Both have a dark side/clone that the battle (Phantom Aqua, Anti-Aqua and Jeanne Alter respectively) despite this they fight through it no matter
Both are members of an organization of light (Guardians of Light and Black Faction, respectively) lead by the heads/leaders of the group (King Mickey and Darnic Prestone Yggdmillennia respectively) to fight against another organization of darkness (Organization XIII and Red Faction, respectively) lead by the main villains of the series (Master Xehanort and Amakusa Shirou Tokisada respectively) in great/historical wars between light and darkness (Keyblade War and Holy Grail War respectively)
Both made sacrifices that came at a great cost (Aqua sacrificed herself to 10 years in the Realm of Darkness and Jeanne sacrificed her life so Sieg can have a change of winning) but through it all both continued to fight for their friends until the very end.
