@Kazedoom : he would need stealth skills to go with it, which he is missing.
@Leo80221 : It says unique skills so I am assuming at least one (my guess Paralysis) is not present or known.
@Boomburst : Rogue's need stealth. His skills are useful, we assume since their mechanics are not known yet, but if your target shots out first it is likely to draw more opponents then you can handle.
@AmericanJedi : long titles are normally web novels which then get adapted to light novels, this is originally a web novel (though this is almost certainly based on a LN adaption), and the grading (which this starts right after) is like 7-8 wn chapters from their titles MTL, which is likely more detailed (on chapter title mentions MP), since manga adaptions tend to cut out allot.