To paticiate you first need to get a wizard letter for creatures and use the powder on you and the other part of the powder you use it on friend and your friend use his powder on you.
The wizard has 3 colors and you need to combine the colours first with the other player/friend to get your choosen wizard....
Orange (yellow/red powder) : 30% party bonus, drop of party items and better chance to create ice mammoth
Green (yellow/blue powder) : all potions has 10% more
Purple (red/blue powder) : all magic creatures has more 25% of exp, beserk potion and bullseye potion will increase to 7 and shield will be -8 and mastermind potion will increase 5.
To get the chess box you just say to any event npc the word “chess”