Saint Seiya: Soldiers' Soul

After you've completed a battle, you will be graded based on your performance during the battle: mainly your Time and remaining health. An S ranking is based on health and time spent. You get an S rank if you earn more than 1000 points in the battle result. 100% health = 1000 points (although in this case a perfect gives +200 bonus for 1200 total) and 0 seconds spent = 1000 points (takes 100 points each second passed), so if you finish with 90% of health and the battle took 50 seconds then you get 900 + 500 = 1400 which would award you an S Rank. The same way if you finish the battle with 10% HP while it took 5 seconds, you will get 100 + 950 = 1050 which would also result in an S rank. Perfect victory always gives S rank since you get at least 1200 points because of the bonus. Getting an S rank is pretty easy when you're playing in the earlier story arcs, especially if you're playing as Shun or Ikki. If you can't get it there, you can also go into Versus mode against a second controller (or a CPU set to Easy difficulty) and fight there to get an S rank. Once you're brought to the Battle Result screen and obtain your first S rank, you will unlock Awakening of Cosmo!.

Obtaining S clear ranks in every fight though, is a bit more challenging. Naturally some characters are better than others, thus making S ranks easier or harder to obtain depending on the character you're playing as. Besides the combat tips I listed in the Roadmap, one helpful tip I can give you is that most episode battles have multiple battles in them. So say for example you started an episode battle as Seiya and won with a B rank, then another battle starts and you're playing as Ikki and obtain and S rank. You would still have an S rank for the Episode as a whole. Not only do you only have to obtain an S rank in one battle for it to count in an Episode, but you can also try obtaining it with a character you prefer, provided that episode has multiple battles. Once you've obtained an S rank in all possible battles across all 4 arcs, the trophy will unlock.