Use Unlimited Arakune for this achievement (you can buy him in the Gallery for 3000$). First, with a second controller, choose Iron Tager, then, int the match, build bar doing it Instant Blocks, so you don't have to harm yourself. Use Arakune anti-air Distortion Drive "inverse f", performed with ↓↘→↓↘→ C. Grab Tager and at the highest point use the Distortion Drive, and then when the moves finish, instantly use another one. With his, you will make more than 100 hits.