Oh right, as a previous onmyouji I should already have my shikigami. I was originally matched with Kazumi, which is fine, a formerly incredibly powerful snake yokai that has weakened over the desire to no longer consume and devour actually sounds like a perfect match for Keito as a partner, both morality and character type make them a hard-boiled duo, but I also notice no one else has really properly decided on their pairs either. Given Raging Fenrir's notes on Yukine, she's also a likely candidate, but usability-wise, Kyorinrin's ability to store knowledge in such a manner is useful for a detective.

Hmmmmmmmm. Well those are the strongest matches for me. Waniguchi can weaponize noise, but there's not much synergy besides tangential combat synergy.

But Keito's meeting with them would've been years ago in Kyoto while learning at the Narumi Detective Agency, so I guess whoever is most compatible with that story would be best.