A general rule that I follow for Demon's Souls & Dark Souls is: if you can't beat a boss (or bring his life close to zero) after 3 attempts, STOP. You'll only frustrate yourself and hate the game if you continue.
You need to leave the boss alone for a while and upgrade your armor/weapons, upgrade your vitality/endurance, or build a different type of weapon to use against him.
As far as the 4 kings are concerned:
1) If you're not dodging their sword attacks, you're doing it wrong. Build endurance and increase stamina regen - Havel's Ring, Dark Wood Grain Ring, Cloranthy Ring, etc.