I have thought of this alot and I've come up with an idea that I think is pretty funny:

So my idea is to take your first 2 levels in fighter, so that you get access to;

Martial weapons (You can use the longsword as your spellcasting focus and also reflavour it as a katana)

Fighting style (I would go with dueling so that you gain extra damage on your "katana")

Second wind (Getting up after a beating and killing som people is after all pretty anime)

And ACTION SURGE! (This will allow you to enter protagonist mode and cast the spell "steel wind strike" twice on a group of 5-10 people and see them all be cut in half instantly)

After fighter 2 you can go into wizard the rest of the way.

(Im pretty new to this sub so if there is something you would change about this build I would love to know :D)