Sunsunger is pretty important. Maybe not in kings fall but nightfalls, strikes, vog and crota as well. PvP takes practice and patients. U can't rez when 3 guardians are on top of u, or right as u die. Void walker just never dies if you have max strength, you get your health back after almost every time u smack someone. In return you never die, kinda like the red death perk without the gun. And now for stormcaller, bassicly the king of PvP along with sunbreaker. Not much needed to be said there. As for pve tho it is for mobs, not bosses.