easiest to solo stuff might be SUM
but the only class can solo 99% of stuff (i dont know about that 1% stuff but there is it somewhere) is BM
the cat can tank low level boss up to under 50 and so does the invisible assassin
however that is not easy up 50 + when boss sometime break your cat aggro and after you directly , worser even if you invisible , invisible doesnt work against high level bosses
so what does the BM has :
animation cancelling technique, one of best dps technique that only learnt by some classes
block , dodge , dodge , dodge .... Staph ...