What role in the party Warlock has?

Island in Maztica – Forgotten Realms

When I have the War Caster feat what is my reach for opportunity attacks with it?

Is this too strong for four level 4s?

What about rogues with two weapon fighting feat using a shield as offhand weapon and getting +3 to AC?

Any advise on how to handle players that don’t play their character’s alignment?

How would you make a feat that allowed you to take 1 class feature you don’t have access to?