Starting off, I want to say that this guide is what WORKED FOR ME personally. There may be other methods of obtaining this cosmetic, but I watched some videos and looked up things online and decided to bring this guide to Steam for those who are struggling or are looking to get this item in particular.

To obtain Sailor Chris, you have to meet a requirement:
Inflict 100k damage to an enemy in one hit. (That'll Leave A Mark Steam achievement)
This is where the rocket launcher comes into play and makes it easier.

The rocket launcher is a quick method of obtaining the Sailor cosmetic for Chris in Raid Mode. The rocket launcher will be available to purchase through the shop once you hit level 9. It is pricey and costs 60k BPs. So just save up all of the points you earn.

There are twenty maps of the 'Chasm' section that you can play as you gain EXP and level up. Obviously you can replay these as much as you may need to reach the desired level, but if you are specifically wanting Sailor Chris, reach level 17.

As soon as you have hit level 17, you should already have purchased a rocket launcher. Once you have it loaded in your weapon kit, go to the character selection and click on Quint Cetcham.



I honestly do not know if you have to choose Quint to achieve this, but from the video source I saw, it was one of the steps you had to obtain. You are free to test this with other characters and see if this works. If it does not work and you don't want to lose your rocket launcher, forfeit the match.

Once you have equipped both Quint and the rocket launcher, load into the first level of Chasm, which is CREW QUARTERS AREA 1. Have your rocket launcher in hand, and when you see the first enemy, shoot them. If you achieve the THAT'LL LEAVE A MARK achievement, congratulations! You will get the cosmetic. Just ease on through the end of the level and kick that gold coin!



I REPEAT: IF YOU DID NOT GET THIS STEAM ACHIEVEMENT, YOU WILL NOT UNLOCK THE SAILOR CHRIS COSMETIC.

CONGRATULATIONS!

You should see this image pop up on your screen after you have finished the level.
You now have Sailor Chris. Life is complete. A tear rolls down your cheek as you take in the beauty.
Now Chris Redfield can fight bioterror while looking like a Scooby snack.
And it's all thanks to your hard work.