Spread rumour over all the seas that 'Erik Bloodaxe' isn't called 'Erik Bloodaxe' for nothing! Your enemies will be so afraid, they will surrender to you as ruler.
Not a good idea. Your brother Haakon the Good is currently ruling over Norway. Because of your blood-thirsty ambitions you are not popular there just now. (Perhaps it's because you murdered two of your brothers – did I forget to mention that?). If you were to return home, you wouldn't exactly receive a hero's welcome.
Follow in the footsteps of your Viking ancestors – make continued brutal attacks on the north and western shores. You will gain loot, people will fear you, and it will boost your army's ego a little.
Play a card.