Record of Agarest War 2

You should be able to this one while doing the He's Dead, Jim trophy. You will need to hit a monster 300 times in one attack. Check your skills and click on the skill to look at its information. Near the bottom each skill will tell you how many hits that skill will do. Pick some skills like Fanatic Rave (44 hits) and Absolute Fierce (42 hits) that will loop over and over to rack up the hits. You could also just spam Arc-En-Ciel over and over on a group of 4+ monsters since each monster will get hit once.