Board Thread:Questions and Answers/@comment-294304-20160918171957/@comment-2063612-20160918224614

I think of it mostly from how the story treats the characters. For Santa Alter, it's just Alter dressed as Santa going around in a parody scenario. In the case of Cu Lancer and Cu Caster, they're two separate incarnations who can potentially interact with each other and such. Even if not as different as Caster and Saber Gilles in core character, they're still different. While swimsuit Kiyohime does have a line referencing regular Kiyohime, you're never going to actually see them act separately in the plot because they're just the same person in different clothing as far as the plot is concerned.

Bride really isn't really that different. Saber Lily, like kid Gil and Alex, is a younger aspect. The "Lily" Servants come from the same core but emphasize a different part of their life. Bride is just "Core Nero - Extra/CCC memories + emphasis on finding a loved one." Those differences really only need a paragraph or two to explain and then everything else is the same. As shown in the main plot, they aren't going to separate the two, so the only place that difference comes into play is probably the interlude.