So maybe the Strain attacks all of the main Scepter 4 cast at once and suddenly all of their swords transform into humans who reflect the holder’s secret inner self. Everyone’s sword looks kinda like a younger version of themselves, like Subaru looks like middle school Fushimi for example. In some cases I think that wouldn’t be so bad – like say Doumyouji’s Excalibur is probably a bit more openly insightful than his master but he’s still pretty carefree and energetic just the way Doumyouji is, or Hidaka’s Grand Slasher X who is pretty much a giant puppy in human form. Then there are others who are somewhat more embarrassing, like Akiyama can’t even bring himself to explain why Taruhi is wearing leather and six inch heels and constantly telling everyone to kneel. Benzai’s Zanshou probably has cat ears on his head and says ‘nyaa’ at the end of every sentence, Benzai keeps getting red faced partly from embarrassment and partly because he is resisting the desire to pat his sword’s head and talk to it in baby talk (and meanwhile Akiyama gets a little jealous because usually he’s the one who gets headpats from Benzai). Enomoto’s sword is a giant nerdy otaku who probably wears a sailor fuku and says 'desu’ a lot, everyone tries to reassure Enomoto by telling him not to worry because after all they all always knew he was a giant nerd and this is no surprise. Gotou’s Pochi is probably just like Gotou but even more chill, which to be honest is kinda worrying for everyone in its own way.
Then there’s Fushimi’s Subaru, who is kinda quiet and shy and clings to Fushimi a lot and everyone is charmed by the realization that secretly Fushimi-san is adorable and just wants to be given attention. Like Fushimi will be snapping at Hidaka for being late with the report while Subaru hovers behind him, then Grand Slasher X smiles brightly at him and waves and soon Subaru is waving shyly back and being a little embarrassed that he was noticed. Subaru is also very attached to Tenrou and looks up to him, Tenrou is basically Munakata but slightly less regal and 200% more dork so there’s a lot of 'Oh, Subaru-kun, come play with these ninja figures with me’ and Subaru walks over staring in amazement at the grand strategic battle that Tenrou is recreating using Munakata’s ninja figures. Munakata of course finds this charming and is pretty much watching over them like a proud daddy watches over his children, pleased that Fushimi-kun secretly appreciates his guidance so much while Fushimi looks away and glares and mutters that he is not looking for any guidance thanks.
When Yata shows up it probably gets even more of a mess because Subaru still wants Tenrou to give him attention but now he also wants Yata to give him attention and suddenly Fushimi has his own sword glaring at him for talking with Misaki too much. Yata finds out about the situation when Awashima shows up at the bar with Kikyo (who is basically a much more cute and girly Awashima who loves adorable things and is big sisterly to everyone while wearing cute hair decs). Yata thought the whole situation sounded funny so he really just stopped by Scepter 4 to tease Fushimi, except then he sees Subaru looking so much like middle school Fushimi that he just has to stop and stare for a moment. Subaru sees him and he just gets the biggest widest smile, brighter than any smile Yata ever saw on the real Fushimi’s face as Subaru runs over like 'Misaki!’ Yata’s all 'um, hi?’ and then Fushimi comes over wanting to know what Yata’s doing here. Yata says he was just stopping by and soon he and Fushimi are arguing a little while Subaru holds onto Yata’s arm and tries to get his attention. Failing that he spots Tenrou and runs over to him, Tenrou asks if Subaru would like to help him with something and Subaru is so excited to be asked, Tenrou calls him cute and pats him on the head and Subaru is just beaming. Yata meanwhile is staring all 'so…that’s how you really feel about your King?’, maybe a little jealous that Subaru let go of him so easily. Fushimi meanwhile would just be irritated at the whole thing, watching Subaru going back and worth between being all clingy towards Tenrou and then clingy to Misaki and probably wanting to be the center of everyone’s attention as much as possible.