Strongest Avatar Trophy in Song of Memories
All Dream 4 You levels are highest
How to unlock Strongest AvatarSee First Battle to learn more about the battle system.
Every time you face off against Neomen, when you use Fight or Skip, you will earn experience points (XP). The exact amount is unknown but after every few fights you complete, you will level up. Levelling up increases your strength but it also increases the Song difficulty and enemy's strength as well. In addition, every few levels you earn will also unlock new Songs to use in battle (see Song's Memories for the full list).
To earn this trophy, all of the D4U Girls need to reach max level, which is level 15. Thankfully, no matter which girl is chosen for any fight, all of the girls will be given equal amounts of XP at the successful conclusion of every battle, even for those who did not participate. Once you have earned enough XP, this trophy will pop immediately upon reaching level 15. Although this is technically doable in one playthrough if you were to grind XP, there is absolutely no reason to do so. You will need to complete many playthroughs to earn the Platinum and, providing you don't Retreat from any fights, you will easily earn this trophy during your 2nd or 3rd playthrough at most with absolutely no need to grind or intentionally search out Neomen to fight. Just remember to use Skip in battles and you'll get this in no time.
Note: In addition to XP and levels, the D4U girls also have an affection/affinity rating system, though it is unclear if this system has any effects on the story or battles. The only benefit we know of seems to be that reaching their max affection rating unlocks 3 brief video messages sent by each girl. While these videos are not needed for any trophy, we still recommend watching them because they add a little more backstory and depth to the D4U girls. The only way to increase their affinity ratings is by choosing them throughout the game when prompted. If you look at our Walkthrough (LINK), you'll note that we have put a different girl for each of the first 5 playthroughs so if you are following our guide, you will unlock these naturally along the way, allowing you to experience everything the game has to offer.
You can view their current affinity rating via the Title Screen: Album => Press or to the D4U Chat tab. Once there, look at the musical notes/stars to the left of each girl and see how many there are, with 1 being the lowest amount of affection and 9 being the maximum. Underneath each girl will be the 3 video messages. The first will unlock at 3 stars, the second at 6 and the third at 9.