As anybody who plays Runescape 3 knows, grotesque souls were recently added into the game.
They are a promotional item added to the game and will only be available from January 27th -> Feb 1st.

You can obtain 50 souls every ten minutes for killing a monster, or 100 souls every ten minutes for killing a slayer task monster.
(They can also be purchased through the grand exchange for about 500gp or lower each.)

Collecting souls allows you to combine them into grotesque armor, each piece costs about 4000 souls or more.
When all pieces are collected, you can upgrade the armor using souls gems (500 souls each) to either tier 2 or tier 3 which will mutate the armors form.
(Tier 3 costs 70 gems)

Pieces of armor you can purchase:


Tier 3 armor (without cape or wings)


This is some pretty sweet armor to grab before February 1st, which is why I'm posting about it so people don't miss out.

All pieces of the armor and the full upgrade takes about ~83,000 souls.
(Armor is fully cosmetic and does not have any stat increases. It is totally for looks.)