TheMixedSMP is a server combined 2 different plugins.
There are Lifesteals, Bliss
Life steal
Everytime you DIED, you Lose a heart
Everytime you kill someone, you Gain one

Bliss
You get a paper when you just joined. Right click to get a random tier 1 gem!
Each Gem Have different abilities.
You can change your gem with Gem Trader. Check SHOP IN GAME!
you can upgrade your gem with Gem Upgrader. Check SHOP IN GAME!

Knowing these, here are some reminds... Watch out who you trust with! Team with people you can trust!
Often join Events... There may be something special and limited there!