... Whether he's real or fake doesn't matter. He is just a man now, but the likelihood of this place stripping powers of Constellations has already been confirmed.

[ Therefore easy to kill and stab? But that isn't what Joonghyuk says or means. Dokja is a Constellation that basically got nerfed, too. ]

You can evaluate him yourself. If he's even half as good as Sherlock Holmes, he may be useful.