All credit for this solution is kosi1200 on Playstation trophies dot org
Complete Bound by Flame in the difficulty mode
Buckle your pants because here comes the Captain difficulty! You should attempt this in your second playthrough when you are familiar with the combat mechanism. In this mode enemies hit hard and react faster. They will most likely kill you in one blow so you need to learn the attack patterns if you want to survive.
Only do the easy side quests because they give you a lot of xp and you can upgrade your character faster.I recommend the Ranger skill tree due to its quickness and power! As a warrior you are really slow and enemies can easily overwhelm you if you're not careful!Enemies will leave you alone when you leave the area so you can take your time, sometimes their health will refill but if you keep killing them one by one then it won't be a problem.You do not have to always kill all enemies in Ranger you can sneak through or run past them.Always take the one companion who suits your play style the most.I recommend upgrading armours and weapons and you should always make potions and traps, however I also recommend saving them for the final boss.
Here's how I killed the final boss:
I went in with 50 health potion and with 40 traps (you don't need this much), when he hits you should instantly heal, after dodging of course.When he is doing his quick dagger combo then you should dodge then instantly block, in most cases he will instakill you.When he is shooting just run around and heal if necessary.When the dragon comes you should plant the whole place with traps if you want things to be easier.When you're fighting the dragon always go for the hands first and of course learn the attack patterns.