Soul Series/Fridge

Fridge Brilliance

 * Now, Ezio appearing in Soul Calibur V may seem right, yet one must note that Soul Edge (the first game) is set decades after Ezio's death (Siegfried was born almost a hundred years after Ezio was born). Brilliance kicks in when you realize the game is actually a program installed in the Animus, hence explaining the "glitches" experienced during Ezio's debut trailer. Besides, what better way to train Desmond by having his ancestor fight samurais, ninjas, demonically-possessed swords and gods? Take note that this kinda allows his appearance in the game to be explained that it is non-canon, as Ezio is already dead by the time SCV rolls around.
 * Oddly enough, according to one interview, "the power of the Animus" was actually Ubisoft's suggestion, while a Soul Calibur community manager in a separate interview noted that there were several undocumented gaps in Ezio's history during the events of Brotherhood (the incarnation used in SCV), suggesting the possibility of Ezio himself traveling in time/space to the Soul Calibur universe.
 * I didn't realize Soulcalibur was a portmanteau of "soul" and "excalibur" until just a couple of months ago. The sudden realization occurred while I was walking home from school, and the face I made was probably the most accurate representation of this thing ever. -User:Crazed Ninja
 * "Soul Calibur", literally, means "spirit blade". "Soul Edge", literally, means "spirit blade". Well, that certainly explains the home title of the original Soul Edge as "Soul Blade", but why do these two swords, clearly completely at odds with each other, have the same name? ...Is a question that was perfectly viable when Soulcalibur II, or III, were the most recent. Then IV comes along and proves some people of being right with their Fridge Brilliance - Soul Calibur has perfectly good reason to have the same name as its nemesis. Not only is it made from a shard of Soul Edge, thereby technically BEING the same sword, but as Seigfried's ending shows, Light Is Not Good - Soul Calibur has the same desires as Soul Edge, it's just made specifically to destroy Soul Edge, so it does so, while at the same time fulfilling its own goals. It's better than Soul Edge by virtue of it being the smarter one, but not by much.
 * In a way, Soul Calibur is the exact opposite of Soul Edge, right? In the earlier games, that seemed to imply since Soul Edge was Always Chaotic Evil Soul Calibur was automatically good. However, Soul Calibur doesn't represent good, it represents Order. And you have to admit, a world  is pretty orderly...
 * Once Soul Calibur's origin in the fourth game is revealed, a lot of characters past actions start to make sense. Algol created Soul Calibur using a piece of Soul Edge, with one purpose: to destroy Soul Edge. It does this the only way it knows how: by picking a host to wield it, and manipulating it into doing what it wants.
 * Pyrrha's theme is entitled 'Wings of Sorrow'. This mirrors Tira's stage theme in her debut appearence, 'Wings of Despair'. Pyrrha's Japanese profile mentions how she continues to fight due to fear that Tira will leave her and she'll be alone again. This mirrors Tira's reason for serving Nightmare, fear of being abandoned, as seen in her SCIV ending.
 * Alpha Patrokolos and Pyrrah Omega's names have the Greek characters appear different order. This is because alpha is the first letter of the Greek alphabet and omega is the last.
 * Christian symbolism aside, that would've made more sense if I believe the Word of God for that naming convention (if I'm not getting my sources wrong) was that Alpha Patroklos uses the original style he learned before trying to imitate his mother's moves whereas Pyrrha Omega represents the finalization of her fighting techniques, thus corresponding to the Alpha and Omega in their names (which, as you said, are the first and last letter of the Greek alphabet).
 * Yoshimitsu  has two taunts in SCV. The first is, "It is I, Yoshimitsu!" The second is, "Evildoer...You shall repent!" The brilliance here is not only does he use the correct taunts for obviously evil characters, such as Nightmare, Tira, etc, but also for Patrokolos. Why is this brilliance? Because in the story mode, Patrokolos was slaying innocents left and right, believing them to be malfested. Yoshimitu's mission statement takes offense to that, to say the least.
 * As of Soul Calibur V, the Korean characters have all apparently left. Of course, know that they know both Soul weapons are evil it makes sense how they aren't interested in pursuing either of the swords anymore.

Fridge Logic

 * There's a lot surrounding the Star Wars characters and their weapons...so we'll start there.
 * It was lampshaded in a promo comic, where Starkiller fought Taki and was shocked his lightsaber didn't instantly destroy her weapons.
 * Pyrrha wasn't returned to her family and grew up without knowing of them...yet she somehow uses her mom's fighting style (with a bit of Cassandra's too since both of Sophitia kids in V will be using bits of both Alexandra sisters styles) how could she know this style without growing up with them. her brother Patroklos probably can be hand-waved off as being Raised by Cassandra after Sophitia dies/vanishes(not clear what happened officially yet.) but not her.
 * It might be implied that there's something about the weapons themselves that gives her the knowledge to fight. Her profile describes her discipline as 'protected by her sword and shield'.
 * Sophitia AND Cassandra's sword skills were both given to them by their sword... which Pyrrha now uses. Patroklos actually.
 * Edgemaster randomly hanging out in Astral Chaos seems to be very odd. Until the artbook revealed than Night Terror is loose in that dimension, and could likely, at any point attempt escape(it doesn't actually think, which may be the only reason it does not), as someone far weaker(Pyrrha) cut the dimension open. Edgemaster is in there to make sure Night Terror stays there. Crosses over into Fridge Horror when you also realize Cassandra is trapped in a world with an insane berserker out to destroy every soul it finds. Even Algol seems to keep his distance.
 * Cervantes, Kilik, and Siegfried have also passed through Astral Chaos at varying points in the series (although Siegfried doesn't count seeing as he was Nightmare at the time and therefore Night Terror wouldn't have existed at that point) without encountering it. That also raises the question of what Night Terror exactly is, seeing how it was Nightmare's One-Winged Angel in III but V's art book indicates it's something completely different, despite it wielding Soul Edge Complete.