1.) With a Shadow Realm Spell card, players can send themselves to the Shadow Realm by right clicking on a blue campfire. This will not drop the captured soul of the player but just use up the card instead. THIS DOES NOT WORK ON MOBS!
(Note: this will teleport the player to the Shadow realm for 5 minutes)

1.) In order to capture the mob, it must be killed by the "Soul Taker" card, turning the card into a "Monster Card."
2.) Each "Monster Card" will have its own attack level. The harder the mob, the higher the attack level potential is, such that mob like a chicken for example might give you an attack level of 1 while a creeper might give you a much higher attack level.
(Note: this now works with boss mobs such as the Ender Dragon and the Wither.)

In order to initiate a battle, both participating players must hold their desired "Monster Card" In their hand. Then one of the players can just simply left click on the other to start the battle. The player whos mob wins, keeps his own card while winning the losers card as well. Yes this means that if you lose, you will lose your card.