How do you get the key for hook coast ?

I'm not sure about the key in hook coast, but to kill jack of blades kill all the minions and when he comes down use assasins rush to get behind him and attack him. Keep doing this until he goes back up and then use multi arrows whilst dodgeing his attacks and shoot him down.
Hope this helps

The Hook Coast key is in a cupboard in the lighthouse near the house you can buy. I found it after smashing in the door to chase after a baddy I don't want to name in case you've not got that far (don't wanna spoil plot - there's little enough of it!). I don't know what will happen if you smash the door in at a time when you're not fighting the big fight (fine and chucked out probably - unless you bribe a guard - oh, sponsor his break I mean! Good luck.

It is easy to kill Jack after you beat him like 12 time lol
I always beat him by hitting him when he charges at you ( use the slow-down time spell makes it easier )
When he gets up in the air use your bow ( use the multiple arrow spell )
He dies in like 3 mins for me
Hope I helped

The key in Hook Coast is in the lighthouse in a cupboard.
Kill the minions guarding him, then use your Melee weapon on him until he retreats to the air. You need about 20 will potions to do it my way. Set your will potions to a hotkey. Cast lightning at him until he dies. As long as you're hitting him with lightning he can't attack you, just use will potions to keep your mana bar up. As long as you have them set to a hotkey you don't ever have to let off with the lightning.