Black and Blue phantoms

So i was playing Demon's Soul yesterday and got invaded by a bleck phantom. My first initial thought was " i have to GTFO" but found that the exit was blocked however, it turned out the bleck phantom was a scrub cuz he fall off a cliff after i used fire magic on him (on purpose maybe...i dunno). This happened in 4-2 .

Then i went to 5-2 which was a gay place by the way cuz u get POISONED! every 30 seconds or so n u cant see shit. Before i went down i touched the soul sign which summoned another player. at first i thot he was pro but then he got killed and died from those huge nigas carrying the club (depraved ones i think). Those guys can really pack a punch

So far i have beaten 4 bosses; Phalanx, Tower Knight, Adjudicator, Leechmonger.

A question: What is the best weapon to use in Demon's Soul (sword, mace, spear????) and how important is magic cuz i've seen people play on youtube n their MP bar is so small compared to health and stamina