What I was thinking:

1. Be born to a wealthy family.
2. Parents shot in front of you.
3. Take off and get trained by ninjas.
4. Return to a company still running well and not stolen from you while you were gone that also has an advanced military prototyping division.
5. Practice with these new weapons/tools until you can competently use them in uneven battles against people trying to kill you while you do your best to avoid killing them.
6. Now go out and fight those battles while keeping your identity secret because no matter how good you get at being Batman, you’re still vulnerable to any situation where your opponents have planned more than you have (eg every ambush and surprise attack).