ScrubNoob is a high elo rengar otp, that uses a weird combination of runes and items, but it works much better than other things. He basically picks fleet footwork, which will help in the jungle clear. You may ask, what, fleet footwork? why dont just pick electrocute, he's an assasin. Well, practically all the assasins in league need electrocute to get a kill, but rengar actually have the enught damage to oneshot without this rune. Ok, you got this, now why fleet footwork. You can proc fleet in jungle, so you can do a full jungle path and end with full hp, ready to kill the enemy toplaner, or whatever. Also, this rune proc instant damage on-hit, so if you R->(while jumping)E->Q->W->Q or the combo you want, the rune will do the damage you may need to kill this squishy objective.

So, the runes are so simple, you have enough damage to oneshot the carries, so lets have better early. This path gives rengar a lot of attack speed, because alarity, the percentage of the rune choice and the empowered Q. Maybe you keep asking to yourself: How can this runes do this amount of damage? Here is the secret.
Celerity, MS --> damage. How does rengar get ms: R + Youmuu + Mobis (rengar's R 1st cast dont activate mobis debuff) + Waterwalking + empowered Q while you are in R (small trick, you can use your empowered Q while you are in the R, and you still invis).

Just look it again: enough damage to kill, some defense to keep alive, just a typical assasin. Nothing much to tell about, while you are in R, use youmuu to get the max damage possible.
About "Are you inting?" items:
Splitpush, with trinity and the attack speed you have, you practically delete turrets in seconds. (Swiftness boots to max damage, mobis would be just to max the 1st hit, because of the debuff)