If Sherlock Holmes was Isekai'd to a fantasy world he would just deduce the rules of this world and get back to solving crimes. He'll find an elf girl sidekick,name her Watson, and pretend like nothing happened.

"If you look closely, you can see traces of chalk dust on the floor. Our murderer must have used a magic circle to kill our victim."

"Actually Holmes, this looks like salt. Quite unusual for a magic circle, since it can be scattered so easily..."

"It tastes like salt too. Good eye Watson. Let us start by visiting the fish mongers."

"Well I would enjoy some fried dragonfish, but how does this help our investigation?"

"A process of elimination, my long-eared friend. There're only two ways for the culprit to get salt in the city. They could have brought it in themselves-"

"But then they'd have to pay the tarrif!"

"Very astute! No, a much likelier option is that they bought it here. Either the docks or the meat market would be the place. And I have a hunch that our culprit is fishy in more ways than one."

"But Holmes, how did you know the merfolk ambassador was the killer?"

"An excellent question, the key was the footprints."

"But he doesn't even have feet!"

"He doesn't as of right now. But you forget, the magic circle."

"I see! The killing spell was a water spear, which normally requires a circle."

"But doesn't if you're already imbued with water magic like our scaly ambassador."

"So the circle..."

"To grant him a pair of feet. For just long enough to leave distinctive footprints in the scattered salt and to make us suspect a two-legged killer."

"By the Goddess, Holmes, you're a genius!"

Makes sense.

Anyway, getting sheer autism vibes from Holmes

Good. That means I wrote him in-character.