Shells are more than just a fashion statement in Mortal Shell. Each of the game's four shells has their own stats, perks, upgrades, abilities, and can completely change your playstyle. Sure, you could technically beat the entire game in husk form, not using a shell at all, but why put yourself at such a disadvantage? Here are the locations of all four shells so you can try them out for yourself and see which one fits you best.
Harros, the Vassal Shell
This is the first shell you will get in the game, and it is essentially forced on you. You'll find Harros slumped on the ground directly on your path after completing the tutorial and enter Fallgrim. He's slightly to the left, if somehow you managed to miss it. This is the most basic, balanced shell in the game that is good for most things, but not excellent in any either. The base stats for this shell are: Durability 5/10, Stamina 5/10, and Resolve 5/10.
Solomon, The Scholar Shell
You will find the next shell after you've reached the tower in the middle of Fallgrim and obtained the Seal and spoken to Sester Genessa. From the tower, exit through the door and make your way through the tunnel straight ahead. You will encounter a miniboss here called a Grisha, but it isn't too difficult as long as you've gotten a handle on the game at this point. If not, you can always sprint past it if you're desperate.
Keep going left down a hill to a little crawlspace hidden under some branches you can break. Squeeze under and you'll find Solomon, The Scholar's shell. This shell is slightly lacking in Stamina, having 5/10, but excellent for Durability and Resolve, which are 7/10 and 10/10 respectively.
Eredim, The Venerable Shell
Once again starting from the tower in Fallgrim, go down the same path we took before to the Grisha, but rather than taking the left after the miniboss, head right. You'll hit another crawlspace to go under to reach the Fallgrim Outskirts. Clear out all the enemies here so they don't bother you, and follow the path to the first fork. Take a left, fighting off more mobs on your way, until you come to the bottom and find Eredim right in front of you laying against a rock.
Eredim, the venerable's shell is perfect for anyone who likes playing the tank. You have 10/10 Durability, but only 3/10 Stamina and Resolve so you'll need to make every swing count.
Tiel, The Acoltye Shell
Because we all know it so well by now, let's start one more time at the tower in Fallgrim. Going out the door, go left until you hit the water and take a right down a path that will eventually lead you to an obelisk marking a fork in the road. Choose to go left, dealing with enemies all the while, until a huge tree adorned with bats comes into view. Head towards it, circling to the other side, where a clearing opens up by a pool of water. Take a dip but stick to the right to find another hidden crawlspace you can uncover. Head through and defeat another miniboss waiting for you on the other side to safely collect this shell.
Rounding out the shells, Tiel's is all about agility and abilities. His stamina is maxed out at 10/10, but Durability and Resolve are a measly 3/10 and 2/10 respectively. If you're a hit and run kind of player, check this one out.