The real fun of this game is after you beat it the first time and you get invaded repeatedly. After my first play through I fought, oh yes, 10 player phantoms in the first base, one after another in near seamless sequence. I also had something like this in 2-1, fighting about 6 guys in a row. I've been through it maybe 4 times, and I have a level 230 character, but once you get that high PvP becomes kind of... well, imbalanced. HP growth past 50 vit is dismal (51-99 vit = 400 total hp like what), and the S-Class weapon bonus makes your weapons way too powerful. Most of the time I get invaded by pushovers that die in one or two hits, but sometimes I'll get invaded by someone that'll one-shot me with hard to dodge magic (homing soul arrow).
Also, if you want a -hard- NPC Black Phantom, Scirvir in 2-2, pure black world tendency. He's hard. I currently use a +5 Crushing Great Sword... holy shit, it has REAL high attack when you get 99 str! <3 Up until then, though, I used the Northern Regalia, with Pure White soul tendency for a nice 540 Attack Power. +5 Dark Silver Shield, Old King Doran armor set, and, for pvp, Eternal Warrior Ring + Ring of Avarice (hey, phantoms give TONS of exp) or, if they're strong, Thief + Graverobbers ring. lolbackstab.