I'm inclined to raise Int, then maybe WC at 8th, and Int again at 12th before I do anything else. In fact, I'm struggling to decide what order to do that in. This is a bladesinger so I probably want War Caster first and to max my Int. That's a clever suggestion but I doubt I could justify a feat for it. War Caster + Booming Blade is a combo along the lines of Polearm Master + Sentinel it works well together, but it's hardly game breaking. It's not a great argument, in terms of the letter of the rules, but it is definitely in keeping with the spirit of the spell being used, which is not intended to automatically deal both primary and secondary damage at the same time.I disagree-I think it fits both the letter and the spirit of the spell. It's not a great argument, in terms of the letter of the rules, but it is definitely in keeping with the spirit of the spell being used, which is not intended to automatically deal both primary and secondary damage at the same time. If you can't choose not to move after being hit with the OA, then it is hard to call that 5' step movement taken 'willingly' after the spell has been cast, because it was committed to before the spell was cast. I think the important part of the spell is that the damage is activated by the creature choosing to move forced movement which doesn't use your move (which you can argue that the 5' move is if the move is deducted before an OA but occurs after the OA) does not trigger movement effects. If the creature wishes to further retreat after moving one space and getting hit with the Booming Blade spell, then it takes the secondary damage. In the end, I would rule that the 5' move which triggered the OA does not also trigger Booming Blade's secondary damage. OA is a special case, since it is an effect that takes place before the cause.

Lightning bolt 5e warcaster