Secret Items:

Mission 0: /
Mission 1: K.o the opponent
Mission 2: Finish the opponent with a Plus Ultra attack
Mission 3: /
Mission 4: K.o the opponent
Mission 5: Finish the opponent with a Plus Ultra attack
Mission 6: K.o the opponent
Mission 7: Use your sidekick attack 3 times and win
Mission 8: Finish the opponent with a EX Plus Ultra attack
Mission 9: /
Mission 10: /
Mission 11: Finish the opponent with a EX Plus Ultra attack
Mission 12: Win with more than 80% HP
Mission 13: /
Mission 14: Finish the opponent with Quirk Technique 1
Mission 15: Win with a Time out
Mission 16: Use your sidekick attack 3 times and win
Mission 17: Use your sidekick attack 3 times and win
Mission 18: /
Mission 19: Win with more than 50% HP
Mission 20: Finish the opponent with a Plus Ultra attack
Mission 21: /
Mission 22: Finish the opponent with a Quirk Technique
Mission 23: Finish the opponent with a Plus Ultra attack
Mission 24: Defeat the opponent in 30 seconds
Mission 25: Win with a time out
Mission 26: Finish the opponent with a Quirk Technique
Mission 27: K.o the opponent

Mission 28: /
Mission 29: Win with a time out (Difficult)
Mission 30: Win with a perfect victory (Difficult)
Mission 31: K.o the opponent
Mission 32: WIn with a perfect victory (Difficult)
Mission 33: Defeat the opponent in 30 seconds (Difficult)
Mission 34: Defeat the opponent in 30 seconds (Difficult)
Mission 35: Finish the opponent with Quirk Technique 1
Mission 36: /
Mission 37: Win with more than 70% HP
Mission 38: Win with a time out (Difficult)
Mission 39: /
Mission 40: Defeat the opponent in 30 seconds (Difficult)
Mission 41: Win with a time out (Difficult)
Mission 42: Finish the opponent with a Plus Ultra attack
Mission 43: /

END

Mission 44: Defeat the opponent in 30 seconds
Mission 45: /
Mission 46: Win with more than 70% HP
Mission 47: Finish the opponent with a Quirk Technique
Mission 48: Win without guarding
Mission 49: Just Guard 3 or more times and win
Mission 50: Finish the opponent with a Plus Ultra attack
Mission 51: Win with more than 70% HP
Mission 52: K.o the opponent
Mission 53: /
Mission 54: Win with more than 70% HP
Mission 55: Defeat the opponent in 30 seconds
Mission 56: Just Guard 3 or more times and win
Mission 57: Finish the opponent with a Plus Ultra attack
Mission 58: /
Mission 59: Win without guarding
Mission 60: /

Mission 61: Finish the opponent with a Plus Ultra attack
Mission 62: Finish the opponent with Quirk Technique 1
Mission 63: /
Mission 64: Win with a perfect victory
Mission 65: Win without using a sidekick
Mission 66: Win with a time out
Mission 67: /
Mission 68: /
Mission 69: Win with more than 70% HP
Mission 70: Win with a time out
Mission 71: /
Mission 72: Finish the opponent with Quirk Technique 1
Mission 73: Finish the opponent with a Plus Ultra attack
Mission 74: /

END

Mission 75: /
Mission 76: Win with a ring out
Mission 77: K.o the opponent
Mission 78: Finish the opponent with a Plus Ultra attack
Mission 79: Finish the opponent with Quirk Technique 1
Mission 80: Freeze the opponent more than once and win
Mission 81: Finish the opponent with Quirk Technique
Mission 82: Finish the opponent with a Plus Ultra attack
Mission 83: Win with more than 80% HP

That's it! You completed every objective and received every secret item!