quote thesavorofpan

ACtually Chie is your major damange dealer in most boss battles,Have her raise her attack and Yosuke raise her hit/envasion and then have her cast Power charge and she can do up to 500 damange on the final boss. With this combination she makes most boss battles mince meat.

Here's the thing though, Chie has a VERY low attack power, in the low 50s by the end game. You can make a Persona on the Protagonist with Power Charge, Matarukaja, Agneyastra, and much better secondary skills but do it all with 60-70 attack power instead. You can save the extra character slot for a better built character.