ok so pretty much holmes is the type that can guess your identity just by looking at you, and when asked why his only reply would be "elementary, my friends" he kinda throws that line a lot actually

mashu gets super excited to learn she got the chance to meet sherlock in the flesh

when theorizing about what class he would be as a servant, she says maybe caster? he says it's a possibility, but archer and saber are just as likely options

holmes appears basically by chance and throws an info dump and gets asked a bunch of questions so his chapter is more about introducing him as a character and him clearing a bunch of doubts and offering new ones

he hints at him playing a much bigger role eventually, that someone allied with the protagonists is a double agent, and explains the true nature of bedivere's character to the player

the guy is pretty mysterious and speaks very formally but when it's time to do an info reveal he gets super excited, to the point where he will stop other people from doing the big reveals before he gets the chance

he also implies he's nothing like what people perceive him asm and even though he's like, mysterious formal and serious, he still stops to make an occasional sarcastic joke, praise people for their deductions and point out the good traits in them!